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Does Any one know what is total current real estate value for those three factories? TIA
Yea, but with financial and sec updates.
But they are in the process of doing that, the last time I traded it from 0.4 to 1.02 in two days , was without company communication, back in April 2014.. But now we have company communication, with PR and 8K.. So who knows how high the PPS will go..
$ABAT
YES , they have not even found out. Good to " THINK OUTSIDE THE BOX " and manifest into reality
could trade back over 3 real quick. look at 5 year chart
guess you have not visited the real website , http://www.zqpt.com/index.html
$ABAT.. Reloading time coming.
Very predictable $$$$$$ oh Weeeeee
Can't wait to see new MM player here..
$ABAT
Now look at how thinly $ABAT trading.. On a 360k ask volume shares it moved up 40%..
Another 360K, with another 40% move..hmm where the PPS would be.
Lets GOOO $ABAT
And they retained new auditing company, according to their 8K release. Once that financial updates are released, $ABAT PPS will soar, can't wait to hit it is book value of $3
Is that $2.5 I see in L2 after 0.59
$ABAT
Interesting press release..$ABAT 2015 updates.
Their come back would be phenomena..
Company release a current report filings.. Their first since 2011..hmm
$ABAT
Cool.. Last pump took this to $1 the same day..
L2 confirming a very thin ask size..
Lets see
$ABAT
The link to the court filings is 3/24/14, why is this just out now if ABAT mgmt really wants to be more transparent, would they be singing this as loud as they can?
The website www.abatelectricscooter.com link is registered to some private organization in Florida...
The pics of the "new" facility show computers with CRT monitors, not sure but would think LCD's would have been used if this is truely a new facility.
Still all the claims about $3 book value per share on this website...based on very old audit.
This 'new' website appears to be a very nice PUMP by some private party?
ABAT PRESEE RELEASE - Press Release
2014-10-28 09:01
Since being attacked in 2011, the senior management of Advanced Battery Technologies Inc. (ABAT) did not focus on responding to or fighting with the attacking short institutions. Rather, ABAT senior management has been dedicated to leading the company to continue developing based on ABAT’s business objectives.
I. Developments in the Past Few Years
1?In December 2011,ABAT finished building Dongguan Qiangqiang in only 8 months. Dongguan Qiangqiang started full production in 2012. It manufactures a variety of products, including Aluminum shell battery core, cylindrical battery, and soft package battery core. Its products achieved the designed capacity and have been sold to various downstream sectors such as cellphone, digital products, and portable power products.
2? Development of Product quality and functionality. Harbin Zhongqiang has successfully developed Nano titanium acid lithium battery that can be quickly charged. The product was developed jointly by Dr. Biying Huang of China Longneng Co. and ABAT, combining Longneng’s battery manufacturing material Li4Ti5O12 and ABAT’s production process. The product has seven characteristics: first, it can be quickly charged, the maximum charge current is around 7C and shortest charge time is roughly 10mins. Second, it can endure larger discharge current. When discharge current is lower than 7C,discharge capacity can reach above 90% of the battery capacity. Third, the product has extremely long normal circulation service life, roughly 8000 to 10000. In addition, the product also has stable discharge platform, low raw material cost, safest battery performance, and a wide working temperature range. Currently, this newly developed product is still in trial phase and we will soon realize industrialized production.
3? Diversified product development and application. Wuxi Angel has developed a new generation of products based on changes in the market. Based on the more than 100 types of existing bicycles and tricycles, Wuxi Angel developed a series of eco-friendly waste-collecting electric vehicles, including floor cleaning series, floor washing series, and waste collection series. The number of product type has reached more than 20 and products have a wide range of applicability. Floor cleaning series include large, medium, and small size vehicles, and are primarily used to clean roads and courtyard. Floor washing series are primarily used to clean indoor floors. Eco-friendly waste-collecting series primarily use internally manufactured battery. Since its introduction into the market, users speak highly of the eco-friendly waste-collecting vehicles. In addition, the company also developed unicycle products and two-wheel standing products, which have entered into domestic and international markets. The above-mentioned products have real environment-friendly and energy-saving effects.
II. Vision on Future Development
1?Based in the new energy industry, the company aims to provide products with efficiency and high quality, expand the scope of applicability, and transit into environment-friendly and energy-saving high-end products.
2?In the next two years, the company aims to increase research and development, develop a new generation of products to satisfy the demands of market, and increase the company’s vitality and viability.
3? The company plans to increase the intensity of product market management to make sure its products satisfy customers’ needs and also expand to and establish in new product markets by providing products with superior quality and realize economic benefits.
4?The company expects to go back to the NASDAQ market in the next two years.
III. Auditing
1?The company terminated its contract with independent auditor EFP Rotenberg in September 2011. As a result, the company did not file any financial statements with the Securities and Exchange Commission in the past few years. After careful consideration and discussions, ABAT Board of Directors has engaged a new independent auditor Paritz & Company to audit its financials in the past few years. The company expects to provide complete financial reports in the first quarter of 2015. We hope our shareholders will review the company financial reports by then. The board apologizes for not being able to provide financial reports in the past few years.
ABAT Board of Directors
October 18, 2014
Form 8-K out. Looks like ABAT might go active again.
Before they got pissed at the way the US was pushing them around, and went dark, they were a few bucks a share, doing millions in battery business.
Might look at ABAT again.
Everyone needs batteries it seems.
Interesting new Seeking Alpha energy storage, batteries etc, article just came out. One of many markets ABAT could tap
http://seekingalpha.com/article/2504355-energy-storage-profiting-from-the-next-mega-market-for-the-power-industry?v=1411054468
ALIBABA AND ABAT - Electric Tricycles with 500W Brushless Differential Motor, 48V20Ah SLA Battery
alibaba has 8000 of these in inventory….. and thats just this item . manufacturer is Wuxi Angell Autocycle Co., Ltd
OMG!! WOW this is HUGE!! just noticed it - look at updated website !! http://www.abatelectricscooter.com/
Shareholders wish many blessings to Chairman Zhigou Fu, CEO Qiang Fu,
ABAT's Management and employees of Advanced Battery.
Congratulations on a Fair Settlement !!!
click below for Court Filings
"Judge Approves Settlement for Nominal Amount and Closes Class Action"
"Plaintiffs Withdraw Appeal Against ABAT's Auditors"
Stock is up 200% in 2014 and has a current price target of $1.00
ABAT Book Value is $3.00 according to most recent filing.
Click Below for More Videos of
ABAT's Dongguan Opening Ceremony on YouTube or
Scroll Down for Slideshow of New Dongguan Facility
seems shares are getting harder to come by. wonder what the deal is? someone , somewhere knows something. If this were to come out of the dark and file? Could move it to over 4 dollars. seen it done before
something still adding a bunch here .... volume stabilizing @ higher increments and growing
In response to your post on the 'lithium coating', I've been holding a very small position in a company that does just that, with patents. Unfortunately they haven't been able to commercialize it yet...EIPC is the ticker. I'm also wondering where ABAT fits into this post if anyone knows/have heard?
Graphene-enhanced anode particulates for
lithium ion batteries
US 20120064409 A1
ABSTRACT
A nano graphene-enhanced particulate for use as
a lithium-ion battery anode active material,
wherein the particulate is formed of a single sheet
of graphene or a plurality of graphene sheets and
a plurality of fine anode active material particles
with a size smaller than 10 µm. The graphene
sheets and the particles are mutually bonded or
agglomerated into the particulate with at least a
graphene sheet embracing the anode active
material particles. The amount of graphene is at
least 0.01% by weight and the amount of the
anode active material is at least 0.1% by weight,
all based on the total weight of the particulate. A
lithium-ion battery having an anode containing
these graphene-enhanced particulates exhibits a
stable charge and discharge cycling response, a
high specific capacity per unit mass, a high first-
cycle efficiency, a high capacity per electrode
volume, and a long cycle life.
DESCRIPTION
This invention is based on research results of a
project supported by the US NSF SBIR-STTR
Program.
FIELD OF THE INVENTION
The present invention relates generally to the field
of lithium-ion batteries and, in particular, to a
nano graphene-enhanced anode for a lithium-ion
battery.
BACKGROUND
The discussion of prior art is primarily based on
the references listed at the end of this
“Background” section.
The most commonly used anode materials for
lithium-ion batteries are natural graphite and
synthetic graphite (artificial graphite) that can be
intercalated with lithium and the resulting
graphite intercalation compound (GIC) may be
expressed as Lix C 6, where x is typically less than
1. The maximum amount of lithium that can be
reversibly intercalated into the interstices between
graphene planes of a perfect graphite crystal
corresponds to x=1, defining a theoretical specific
capacity of 372 mAh/g.
Graphite or carbon anodes can have a long cycle
life due to the presence of a protective surface-
electrolyte interface layer (SEI), which results
from the reaction between lithium and the
electrolyte (or between lithium and the anode
surface/edge atoms or functional groups) during
the first several charge-discharge cycles. The
lithium in this reaction comes from some of the
lithium ions originally intended for the charge
transfer purpose. As the SEI is formed, the lithium
ions become part of the inert SEI layer and
become irreversible, i.e. they can no longer be the
active element for charge transfer. Therefore, it is
desirable to use a minimum amount of lithium for
the formation of an effective SEI layer. In addition
to SEI formation, the irreversible capacity loss Q ir
can also be attributed to graphite exfoliation
caused by electrolyte/solvent co-intercalation and
other side reactions.
In addition to carbon- or graphite-based anode
materials, other inorganic materials that have
been evaluated for potential anode applications
include metal oxides, metal nitrides, metal
sulfides, and the like, and a range of metals,
metal alloys, and intermetallic compounds that
can accommodate lithium atoms/ions or react
with lithium. Among these materials, lithium
alloys having a composition formula of LiaA (A is
a metal such as Al, and “a” satisfies 0<a?5) are
of great interest due to their high theoretical
capacity, e.g., Li4Si (3,829 mAh/g), Li4.4Si (4,200
mAh/g), Li4.4Ge (1,623 mAh/g), Li4.4 Sn (993
mAh/g), Li3Cd (715 mAh/g), Li3Sb (660 mAh/g),
Li4.4 Pb (569 mAh/g), LiZn (410 mAh/g), and
Li3Bi (385 mAh/g). However, in the anodes
composed of these materials, severe pulverization
(fragmentation of the alloy particles) occurs
during the charge and discharge cycles due to
expansion and contraction of the anode active
material induced by the insertion and extraction
of the lithium ions in and out of the anode active
material. The expansion and contraction, and the
resulting pulverization of active material particles
lead to loss of contacts between active particles
and conductive additives and loss of contacts
between the anode active material and its current
collector. This degradation phenomenon is
illustrated in FIG. 1. These adverse effects result
in a significantly shortened charge-discharge
cycle life.
To overcome the problems associated with such
mechanical degradation, three technical
approaches have been followed:
(1) reducing the size of the active material
particle, presumably for the purpose of reducing
the strain energy that can be stored in a particle,
which is a driving force for crack formation in the
particle. However, a reduced particle size implies
a higher surface area available for potentially
reacting with the liquid electrolyte. Such a
reaction is undesirable since it is a source of
irreversible capacity loss.
(2) depositing the electrode active material in a
thin film form directly onto a current collector,
such as a copper foil. However, such a thin film
structure with an extremely small thickness-
direction dimension (typically much smaller than
500 nm) implies that only a small amount of
active material can be incorporated in an
electrode (given the same electrode or current
collector surface area), providing a low total
lithium storage capacity (even though the
capacity per unit mass can be large).
(3) using a composite composed of small
electrode active particles supported with or
protected by a less active or non-active matrix,
e.g., carbon-coated Si particles [Refs. 1-3], sol
gel graphite-protected Si, metal oxide-coated Si
or Sn [Ref. 4], and monomer-coated Sn nano
particles [Ref 5]. Presumably, the protective
matrix provides a cushioning effect for particle
expansion or shrinkage, and prevents the
electrolyte from contacting and reacting with the
electrode active material. Examples of anode
active particles are Si, Sn, and SnO 2. However,
most of prior art composite electrodes have
deficiencies in some ways, e.g., in most cases,
less than satisfactory reversible capacity, poor
cycling stability, high irreversible capacity,
ineffectiveness in reducing the internal stress or
strain during the lithium ion insertion and
extraction steps, and other undesirable side
effects.
It may be further noted that the coating or matrix
materials used to protect active particles (such
as Si and Sn) are carbon, sol gel graphite, metal
oxide, monomer, ceramic, and lithium oxide.
These protective materials are all very brittle,
weak (of low strength), and/or non-conducting
(e.g., ceramic or oxide coating). Ideally, the
protective material should meet the following
requirements: (a) The coating or matrix material
should be of high strength and stiffness so that it
can help to refrain the electrode active material
particles, when lithiated, from expanding to an
excessive extent. (b) The protective material
should also have high fracture toughness or high
resistance to crack formation to avoid
disintegration during repeated cycling. (c) The
protective material must be inert (inactive) with
respect to the electrolyte, but be a good lithium
ion conductor. (d) The protective material must
not provide any significant amount of defect sites
that irreversibly trap lithium ions. The prior art
protective materials all fall short of these
requirements. Hence, it was not surprising to
observe that the resulting anode typically shows
a reversible specific capacity much lower than
expected. In many cases, the first-cycle efficiency
is extremely low (mostly lower than 80% and
some even lower than 60%). Furthermore, in most
cases, the electrode was not capable of operating
for a large number of cycles. Additionally, most of
these electrodes are not high-rate capable,
exhibiting unacceptably low capacity at a high
discharge rate.
Complex composite particles of particular interest
are a mixture of separate Si and graphite particles
dispersed in a carbon matrix prepared by J. Yang,
et al. [Ref. 6], Wen, et al [Ref. 7] and by Mao, et
al. [Ref. 8], carbon matrix containing complex
nano Si (protected by oxide) and graphite
particles dispersed therein [Ref. 9], and carbon-
coated Si particles distributed on a surface of
graphite particles [Ref. 10]. Again, these complex
composite particles led to a low specific capacity
or for up to a small number of cycles only. It
appears that carbon by itself is relatively weak
and brittle and the presence of micron-sized
graphite particles does not improve the
mechanical integrity of carbon since graphite
particles are themselves relatively weak. Graphite
was used in these cases presumably for the
purpose of improving the electrical conductivity of
the anode material. Furthermore, polymeric
carbon, amorphous carbon, or pre-graphitic
carbon may have too many lithium-trapping sites
that irreversibly capture lithium during the first
few cycles, resulting in excessive irreversibility.
In summary, the prior art has not demonstrated a
composite material that has all or most of the
properties desired for use as an anode material in
a lithium-ion battery. Thus, there is an urgent
and continuing need for a new anode for the
lithium-ion battery that has a high cycle life, high
reversible capacity, low irreversible capacity, small
particle sizes (for high-rate capacity), and
compatibility with commonly used electrolytes.
There is also a need for a method of readily or
easily producing such a material in large
quantities.
In response to these needs, one of our earlier
applications [14] discloses a nano-scaled
graphene platelet-based composite composition
for use as a lithium ion battery anode. This
composition comprises: (a) micron- or
nanometer-scaled particles or coating of an
anode active material; and (b) a plurality of nano-
scaled graphene platelets (NGPs), wherein a
platelet comprises a graphene sheet or a stack of
graphene sheets having a platelet thickness less
than 100 nm and wherein the particles or coating
are physically attached or chemically bonded to
NGPs. Nano graphene platelets (NGPs) are
individual graphene sheets (individual basal
planes of carbon atoms isolated from a graphite
crystal) or stacks of multiple graphene planes
bonded together in the thickness direction. The
NGPs have a thickness less than 100 nm and a
length, width, or diameter that can be greater or
less than 10 µm. The thickness is more preferably
less than 10 nm and most preferably less than 1
nm.
Disclosed in another patent application of ours
[15] is a more specific composition, which is
composed of a 3-D network of NGPs and/or other
conductive filaments and select anode active
material particles that are bonded to these NGPs
or filaments through a conductive binder. Yet
another application [16], as schematically shown
in FIGS. 2(A) and 2(B), provides a nano
graphene-reinforced nanocomposite solid particle
composition containing NGPs and electrode active
material particles, which are both dispersed in a
protective matrix (e.g. a carbon matrix).
After our discovery of graphene providing an
outstanding support for anode active materials
[14-16], many subsequent studies by others [e.g.
17-21] have confirmed the effectiveness of this
approach. For instance, Wang, et al. [17]
investigated self-assembled TiO 2-graphene hybrid
nanostructures for enhanced Li-ion insertion. The
results indicate that, as compared with the pure
TiO 2 phase, the specific capacity of the hybrid
was more than doubled at high charge rates. The
improved capacity at a high charge-discharge
rate was attributed to increased electrode
conductivity afforded by a percolated graphene
network embedded into the metal oxide
electrodes. However, all these earlier studies were
focused solely on providing a network of electron-
conducting paths for the anode active material
particles and failed to address other critical
issues, such as ease of anode material
processing, electrode processability, electrode tap
density (the ability to pack a dense mass into a
given volume), and long-term cycling stability.
For instance, the method of preparing self-
assembled hybrid nanostructures [17] is not
amenable to mass production. The anode material
particle-coated graphene sheets alone are not
suitable for electrode fabrication (due to the
difficulty in coating the materials onto a current
collector), and the resulting electrodes are
typically too low in the tap density. Paper-based
composite structures [21] are not compatible with
current lithium-ion battery production equipment.
These are all critically important issues that must
be addressed in a real battery manufacturing
environment.
Herein reported is a further improved anode
composition that provides not only a robust 3-D
network of electron-conducting paths and high
conductivity, but also enables the anode materials
to be readily made into electrodes with a high
electrode tap density and long-term cycling
stability. Both the reversible capacity and the
first-cycle efficiency are also significantly
improved over those of state-of-the-art anode
materials.
REFERENCES
1. M. Yoshio, et al., “Carbon-coated Si as a
Lithium-Ion Battery Anode Material,” J. of the
Electrochemical Soc., 149 (12) (2002) A1598-
A1603.
2. N. Dimov, et al., “Characterization of Carbon-
coated Silicon Structural Evolution and Possible
Limitations,” J. of Power source, 114 (2003)
88-95.
3. N. Dimov, et al., “Carbon-coated Silicon as
Anode Material for Lithium Ion Batteries:
Advantages and Limitations,” Electrochimica Acta,
48 (2003) 1579-1587.
4. H. Yamaguchi, “Anode Material, Anode and
Battery,” US 2007/0122701 (Pub. May 31, 2007).
5. H. Kim, et al., “Anode Active Material,
Manufacturing Method Thereof, and Lithium
Battery Using the Anode Active Material,” US
2007/0020519 (Pub. Jan. 25, 2007).
6. J. Yang, et al., “Si/C Composites for High-
Capacity Lithium Storage Materials,”
Electrochemical and Solid-State Letters, 6 (8)
(2003) A154-A156.
7. Z. S. Wen, et al., “High-capacity Silicon/Carbon
Composite Anode Materials for Lithium Ion
Batteries,” Electrochemistry Communications, 5
(2003) 165-168.
8. Z. Mao, et al. “Carbon-coated Silicon Particle
Powder as the Anode Material for Lithium
Batteries and the Method of Making the Same,”
US 2005/0136330 (Jun. 23, 2005).
9. H. Y. Lee and S. M. Lee, “Carbon-Coated
Nano-Si Dispersed Oxides/Graphite Composites
as Anode Material for Lithium Ion Batteries,”
Electrochemistry Communications, 6 (2004)
465-469.
10. K. Matsubara, et al., “Carbonaceous Material
and Lithium Secondary Batteries Comprising
Same,” U.S. Pat. No. 6,733,922 (May 11, 2004).
11. B. Z. Jang and W. C. Huang, “Nano-scaled
Graphene Plates,” U.S. Pat. No. 7,071,258 (Jul. 4,
2006).
12. B. Z. Jang, L. X. Yang, S. C. Wong, and Y. J.
Bai, “Process for Producing Nano-scaled
Graphene Plates,” U.S. patent application Ser.
No. 10/858,814 (Jun. 3, 2004).
13. A. Zhamu, J. Jang, J. Shi,and B. Z. Jang,
“Method of Producing Ultra-thin Nano-Scaled
Graphene Platelets,” U.S. patent application Ser.
No. 11/879,680 (Jul. 19, 2007).
14. Aruna Zhamu and Bor Z. Jang, “Nano
Graphene Platelet-Based Composite Anode
Compositions for Lithium Ion Batteries,” U.S.
patent application Ser. 11/982,672 (Nov. 5,
2007); Now U.S. Pat. No. 7,745,047 (Jun. 29,
2010).
15. Jinjun Shi, Aruna Zhamu and Bor Z. Jang,
“Conductive Nanocomposite-based Electrodes for
Lithium Batteries,” U.S. patent application Ser.
No. 12/156,644 (Jun. 4, 2008).
16. Aruna Zhamu, Bor Z. Jang, and Jinjun Shi,
“Nano Graphene Reinforced Nanocomposite for
Lithium Battery Electrodes,” U.S. patent
application Ser. No. 12/315,555 (Dec. 4, 2008).
17. D. Wang, et al. “Self-Assembled TiO 2-
Graphene Hybrid Nanostructures for Enhanced Li-
Ion Insertion.” ACS Nano, 3 (2009) 907-914.
18. S. M. Paek, et al. “Enhanced Cyclic
Performance and Lithium Storage Capacity of
SnO 2/Graphene Nanoporous Electrodes with
Three-Dimensionally Delaminated Flexible
Structure,” Nano Letters, 9 (2009) 72-75.
19. J. Yao, et al “In Situ Chemical Synthesis of
SnO 2—Graphene Nanocomposite as Anode
Materials for Lithium-Ion Batteries,”
Electrochemistry Communications, 11 (2009)
1849-1852.
20. G. Wang, et al., “Sn/Graphene Nanocomposite
with 3D Architecture for Enhanced Reversible
Lithium Storage Batteries,” J. Materials
Chemistry, 19 (2009) 8378-8384.
21. J. K. Lee, et al., “Silicon nanoparticles-
graphene paper composites for Li ion battery
anodes,” Chem. Commun., 46 (2010) 2025-2027.
SUMMARY OF THE INVENTION
The present invention provides a nano graphene-
enhanced particulate for use as a lithium-ion
battery anode active material, wherein the
particulate is formed of a single or a plurality of
graphene sheets and a plurality of fine anode
active material particles (with a size smaller than
10 µm, preferably smaller than 1 µm, and most
preferably smaller than 100 nm). The graphene
sheets and the fine active particles (herein
referred to as primary particles) are mutually
bonded or agglomerated into the particulate
(herein referred to as a secondary particle) with
at least a graphene sheet embracing the anode
active material particles. Graphene is in an
amount of at least 0.01% by weight (preferably at
least 0.1% by weight and more preferably at least
1% by weight, but typically much lower than 99%,
more typically less than 90%, and most typically
less than 70% by weight) and the anode active
material is in an amount of at least 0.1% by
weight (typically higher than 10% by weight), all
based on the total weight of the particulate. The
particulate is approximately spherical or
ellipsoidal in shape.
The graphene sheets inside or on the exterior
surface of this particulate preferably comprise
single-layer graphene or few-layer graphene,
wherein few-layer graphene is defined as a
graphene platelet formed of less than 10 graphene
planes of carbon atoms.
There is no restriction on the type and nature of
the anode active material that can be used to
practice the present invention. Most preferably,
the anode active material may comprise Sn or Si
as a primary element with Si or Sn content no
less than 20% by weight based on the total
weight of the anode active material. However, the
anode active material may comprise an element
selected from Si, Ge, Sn, Cd, Sb, Pb, Bi, Zn, Al, Co,
Ni, or Ti. Specifically, the anode active material
may be selected from the group consisting of:
(a) silicon (Si), germanium (Ge), tin (Sn), lead
(Pb), antimony (Sb), bismuth (Bi), zinc (Zn),
aluminum (Al), titanium (Ti), Nickel (Ni), cobalt
(Co), and cadmium (Cd);
(b) alloys or intermetallic compounds of Si, Ge,
Sn, Pb, Sb, Bi, Zn, Al, Ti, Co, Ni, or Cd with other
elements, wherein said alloys or compounds are
stoichiometric or non-stoichiometric;
(c) oxides, carbides, nitrides, sulfides, phosphides,
selenides, and tellurides of Si, Ge, Sn, Pb, Sb, Bi,
Zn, Al, Ti, Co, Ni, Fe, or Cd, and their mixtures,
composites, or lithium-containing composites;
(d) salts and hydroxides of Sn;
(e) lithium titanate, lithium manganate, lithium
aluminate, lithium-containing titanium oxide,
lithium transition metal oxide; and
(f) combinations thereof.
The anode active material particles in the
particulate preferably have a dimension smaller
than 1 µm, further preferably smaller than 100
nm. A particularly useful class of the anode active
material for electric vehicle batteries is lithiated
titanium dioxide, lithiated titanium oxide, lithium
titanate, or Li4 Ti5O 12 due to their high-rate
capability (can be charged and discharged in high
rates).
The anode active material may also be selected
from particles of natural graphite, artificial
graphite, meso-carbon micro-bead (MCMB),
graphitic coke, meso-phase carbon, hard carbon,
soft carbon, polymeric carbon, carbon or graphite
fiber segments, carbon nano-fiber or graphitic
nano-fiber, carbon nano-tube, or a combination
thereof. We have surprisingly observed that all
these carbon-based materials can be embraced
inside an envelope or skin constituted by a
graphene sheet or multiple graphene sheets.
The particulate may further comprise therein a
carbon or graphite material in electronic contact
with the anode active material and a graphene
sheet. The carbon or graphite material may be
coated on or in contact with at least one of the
anode active material particles or a graphene
sheet, wherein the carbon or graphite material is
selected from polymeric carbon, amorphous
carbon, chemical vapor deposition carbon, coal
tar pitch, petroleum pitch, meso-phase pitch,
carbon black, coke, acetylene black, activated
carbon, fine expanded graphite particle with a
dimension smaller than 100 nm, artificial graphite
particle, natural graphite particle, or a
combination thereof. The polymeric carbon or
amorphous carbon may be obtained from
pyrolyzation of a polymer selected from the group
consisting of phenol-formaldehyde,
polyacrylonitrile, styrene-based polymers,
cellulosic polymers, epoxy resins, and
combinations thereof.
The nano graphene platelets may be obtained
from intercalation and exfoliation of a layered or
laminar graphite to produce graphite worms
composed of exfoliated flakes that are loosely
interconnected. The exfoliation is followed by
separation of these flakes or platelets. The
laminar graphite may be selected from a natural
graphite, synthetic graphite, highly oriented
pyrolytic graphite, graphite fiber, carbon fiber,
carbon nano-fiber, graphitic nano-fiber, spherical
graphite or graphite globule, meso-phase micro-
bead, meso-phase pitch, graphitic coke, or
graphitized polymeric carbon. Natural graphite is
particularly desirable due to its abundant
availability and low cost.
Another embodiment of the present invention is a
process for preparing the presently invented
graphene-enhanced anode particulate. In one
preferred embodiment, the process comprises: (a)
preparing a precursor mixture of graphene or
graphene precursor with an anode active material
or anode active material precursor; and (b)
thermally and/or chemically converting the
precursor mixture to the graphene-enhanced
anode particulate. The step of preparing a
precursor mixture may comprise preparing a
suspension of graphene or graphene precursor
(e.g. graphene oxide or graphene fluoride) in a
liquid medium and mixing an anode active
material or anode active material precursor in the
suspension to form a multi-component
suspension. The process may further comprise a
step of drying the multi-component suspension to
form the precursor mixture.
The step of drying the multi-component
suspension to form the precursor mixture is most
preferably conducted using a spray-drying, spray-
pyrolysis, fluidized-bed drying procedure, or any
procedure that involves an atomization or
aerosolizing step. The step of converting may
comprise a sintering, heat-treatment, spray-
pyrolysis, or fluidized bed drying or heating
procedure. The step of converting may comprise a
procedure of chemically or thermally reducing the
graphene precursor to reduce or eliminate oxygen
or fluorine content and other non-carbon
elements of the graphene precursor, which
graphene precursor may contain graphene oxide
or graphene fluoride. Upon conversion, the
graphene in the particulate has an oxygen content
typically less than 5% by weight.
In another preferred embodiment, the step of
preparing the precursor mixture may comprise:
(A) dispersing or exposing a laminar graphite
material in a fluid of an intercalant and/or an
oxidant to obtain a graphite intercalation
compound (GIC) or graphite oxide (GO); (B)
exposing the resulting GIC or GO to a thermal
shock at temperature for a period of time
sufficient to obtain exfoliated graphite or graphite
worms; (C) dispersing the exfoliated graphite or
graphite worms in a liquid medium containing an
acid, an oxidizing agent, and/or an organic
solvent at a desired temperature for a duration of
time until the exfoliated graphite is converted into
a graphene oxide dissolved in the liquid medium
to form a graphene solution; and (D) adding a
desired amount of said anode precursor material
to the graphene solution to form the precursor
mixture in a suspension, slurry or paste form.
Alternatively, the process may begin with the
preparation of pristine graphene, instead of
graphene oxide. In other words, the step of
preparing the precursor mixture comprises: (a)
preparing a suspension containing pristine nano
graphene platelets (NGPs) dispersed in a liquid
medium; (b) adding an acid and/or an oxidizing
agent into the suspension at a temperature for a
period of time sufficient to obtain a graphene
solution or suspension; and (c) adding a desired
amount of an anode active material or precursor
in the graphene solution or suspension to form a
paste or slurry.
Another embodiment of the present invention is a
lithium ion battery anode comprising multiple
nano graphene-enhanced anode particulates as
described above. A further embodiment is a
lithium ion battery comprising such an anode, a
cathode, a separator disposed between the anode
and the cathode, and electrolyte in physical
contact with both the anode and the cathode.
In a particularly preferred embodiment, a lithium
ion battery may comprise an anode featuring
graphene-enhanced particulates of anode active
particles and a cathode featuring graphene-
enhanced cathode particulates as well. A cathode
particulate is formed of a single graphene sheet
or a plurality of graphene sheets and a plurality of
fine cathode active material particles with a size
smaller than 10 µm (preferably smaller than 1 µm
and more preferably smaller than 100 nm). The
graphene sheets and the particles are mutually
bonded or agglomerated into the cathode
particulate with at least a graphene sheet
embracing the cathode active material particles
inside the particulate. The graphene is in an
amount of from 0.01% to 30% by weight based on
the cathode particulate weight.
There is also no particular restriction on the type
and nature of the cathode active material, which
can be selected for practicing the present
invention. The cathode active material may be
selected from the group consisting of lithium
cobalt oxide, lithium nickel oxide, lithium
manganese oxide, lithium vanadium oxide,
lithium-mixed metal oxide, lithium iron
phosphate, lithium manganese phosphate, lithium
vanadium phosphate, lithium mixed metal
phosphates, metal sulfides, and combinations
thereof
When the graphene-enhanced anode particulate
contains Si as an anode active material
(preferably in a sub-micron or nano particle
form), according to a preferred embodiment of the
present invention, one can achieve a reversible
specific capacity of greater than 1,000 mAh/g for
longer than 500 cycles and, in many cases, even
greater than 2,000 mAh/g, calculated on the basis
of the total particulate anode weight. The anodes
featuring these graphene-enhanced particulates
also exhibit a high tap density. The embracing
graphene sheets also appear to be capable of
preventing the electrolyte from detrimentally
reacting with the anode active material
(otherwise, such a reaction is a major cause for
the poor first-cycle efficiency). Equally
importantly, the anode slurry, containing
particulates and a binder (PVDF) dispersed in a
solvent (NMP), has flow characteristics (viscosity,
consistency, etc) that are conducive to the
formation of electrodes using existing electrode-
coating machines. This is not the case of those
anode active particle-loaded graphene sheets
reported by the prior art workers.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 Schematic of a prior art anode active
material (e.g., Si particles) that tends to undergo
pulverization during battery charge-discharge
cycling.
FIG. 2 Two prior art nanocomposite particles: (A)
A spherical nanocomposite particle comprising
electro-active materials (e.g., Si nano particles)
and NGPs dispersed in a protective matrix (e.g.,
amorphous carbon); (B) A spherical
nanocomposite particle comprising electro-active
materials (e.g., Si nano-wires) and NGPs
dispersed in a protective matrix (e.g., amorphous
carbon);
FIG. 3 (A) Schematic of a graphene-enhanced
anode particulate according to a preferred
embodiment of the present invention and (B)
another particulate according to another preferred
embodiment of the present invention (containing
some amount of a carbon or graphite material).
FIG. 4 SEM images of (A) a simple mixture of
primary Si particles and fine graphite particles
without being embraced by graphene sheets; (B)
graphene-enhanced particulates comprising
graphene sheets inside the particulate and on the
exterior surface of the particulate, according to
one preferred embodiment of the present
invention; (C) a higher-magnification SEM image
of graphene-enhanced particulates. Graphene
sheets embrace and protect the primary particles
to form secondary particles (particulates) that are
easier to handle in a real anode production
environment. The embracing graphene sheets
also prevent Si nano particles from chemically
reacting with the electrolyte.
FIG. 5 An SEM image of graphene-enhanced
particulates containing therein Co3O 4 and carbon
black particles embraced by graphene sheets: (A)
a lower-magnification image demonstrating
uniform particle sizes: (B) a higher-magnification
SEM image. We found that these more or less
spherical particles can be easily handled and
made into electrodes using existing battery
electrode coating machines. No unusual or
specialty equipment is required. The resulting
electrodes also exhibit a high tap density.
FIG. 6 SEM image of an anode particulate with tin
oxide primary particles embraced by graphene
sheets.
FIG. 7 (A) Schematic of prior art layered Co3 O 4/
graphene composites; and (B) Presently invented
graphene-enhanced particulates.
FIG. 8 Charge-discharge cycling behaviors of
battery cells having an anode featuring graphene-
enhanced particulates, layered Co3O 4/graphene
composites, and bare Co3O 4 particles,
respectively.
FIG. 9 Cycling behaviors of graphene-enhanced
SnO 2 particulates of the present invention and
SnO 2-graphene composites prepared according to
a prior art method.
FIG. 10 The capacity decay curves of three pouch
cells: Cell-8 (both the anode and the cathode
featuring graphene-enhanced particulates), CC-1
(only the anode featuring graphene-enhanced
particulates), and CC-2 (only the cathode
featuring graphene-enhanced particulates).
DETAILED DESCRIPTION OF PREFERRED
EMBODIMENTS
This invention is related to electrode materials for
the high-capacity lithium secondary battery,
which is preferably a secondary battery based on
a non-aqueous electrolyte or a polymer gel
electrolyte. The shape of a lithium secondary
battery can be cylindrical, square, button-like, etc.
The present invention is not limited to any battery
shape or configuration.
The present invention provides a nano graphene-
enhanced particulate (secondary particle) for use
as a lithium-ion battery anode material, wherein
the particulate is formed of a single or a plurality
of graphene sheets and a plurality of fine anode
active material particles (primary particles, with a
size smaller than 10 µm, preferably smaller than 1
µm, and most preferably smaller than 100 nm).
The graphene sheets and the particles are
mutually bonded or agglomerated into the
particulate with at least a graphene sheet
embracing the anode active material particles
(FIG. 3(A)). Graphene is in an amount of at least
0.01% by weight (preferably at least 0.1% by
weight and more preferably at least 1% by weight,
but typically less than 99% by weight) and the
anode active material is in an amount of at least
0.1% by weight, all based on the total weight of
the particulate. The particulate is approximately
spherical or ellipsoidal in shape. The graphene
material in or on this particulate preferably
comprises single-layer graphene or few-layer
graphene, wherein few-layer graphene is defined
as a graphene platelet formed of less than 10
graphene planes of carbon atoms. In addition to
an anode active material (e.g. Si particles), a
carbon or graphite material may be added to the
interior of the particulate (FIG. 3(B)). This carbon
or graphite material in a fine particle or thin
coating form provides additional protection
(additional electron-conducting paths, additional
cushioning effect, and additional shielding against
undesirable reactions with electrolyte). Graphite
and carbon materials can also be an anode active
material.
A nano graphene platelet (NGP) or nano graphene
sheet is composed of one basal plane (graphene
plane) or multiple basal planes stacked together
in the thickness direction. In a graphene plane,
carbon atoms occupy a 2-D hexagonal lattice in
which carbon atoms are bonded together through
strong in-plane covalent bonds. In the c-axis or
thickness direction, these graphene planes may
be weakly bonded together through van der Waals
forces. An NGP can have a platelet thickness from
less than 0.34 nm (single layer) to 100 nm
(multi-layer). For the present electrode use, the
preferred thickness is <10 nm and most preferably
<3 nm or 10 layers). The presently invented
graphene-enhanced particulate preferably
contains mostly single-layer graphene, but could
make use of some few-layer graphene (less than
10 layers). The graphene sheet may contain a
small amount (typically <25% by weight) of non-
carbon elements, such as hydrogen, fluorine, and
oxygen, which are attached to an edge or surface
of the graphene plane. Graphene was recently
discovered to exhibit the highest thermal
conductivity of all existing materials. In addition
to the electrical conductivity, this high thermal
conductivity is clearly an advantageous property
that could not be achieved by any other type of
conductive additives.
Graphene sheets may be oxidized to various
extents during their preparation, resulting in
graphite oxide (GO) or graphene oxide. Hence, in
the present context, graphene preferably or
primarily refers to those graphene sheets
containing no or low oxygen content; but, they
can include GO of various oxygen contents.
Further, graphene may be fluorinated to a
controlled extent to obtain graphite fluoride.
The NGPs may be obtained from exfoliation and
platelet separation of a natural graphite, synthetic
graphite, highly oriented pyrolytic graphite,
graphite fiber, carbon fiber, carbon nano-fiber,
graphitic nano-fiber, spherical graphite or graphite
globule, meso-phase micro-bead, meso-phase
pitch, graphitic coke, or graphitized polymeric
carbon.
For anode applications, the electrode active
material preferably comprises an anode active
material selected from the group consisting of: (a)
silicon (Si), germanium (Ge), tin (Sn), lead (Pb),
antimony (Sb), bismuth (Bi), zinc (Zn), aluminum
(Al), titanium (Ti), Nickel (Ni), cobalt (Co), and
cadmium (Cd); (b) alloys or intermetallic
compounds of Si, Ge, Sn, Pb, Sb, Bi, Zn, Al, Ti, Ni,
Co, or Cd with other elements, wherein the alloys
or compounds are stoichiometric or non-
stoichiometric; (c) oxides, carbides, nitrides,
sulfides, phosphides, selenides, and tellurides of
Si, Ge, Sn, Pb, Sb, Bi, Zn, Al, Fe, Ti, Ni, Co, or Cd,
and their mixtures or composites; and (d)
combinations thereof There is essentially no
constraint on the type and nature of the anode
active material that can be used in practicing the
present invention.
FIG. 4(A) shows an SEM image of a simple
mixture of primary Si particles and fine graphite
particles without being embraced by graphene
sheets. In contrast, FIG. 4(B) and FIG. 4(C) show
graphene-enhanced particulates comprising
graphene sheets in and around the particulate.
Graphene sheets embrace and protect the primary
particles to form secondary particles
(particulates) that are easier to handle in a real
anode production environment. The embracing
graphene sheets also prevent Si nano particles
from chemically reacting with the electrolyte. The
notion that the exterior surface is embraced with
highly conductive graphene sheets implies that
these sheets can naturally form a 3-D network of
electron-conducting paths when multiple
particulates are packed together in an anode.
FIG. 5 shows SEM images of graphene-enhanced
particulates containing therein Co3O 4 and carbon
black particles embraced by graphene sheets.
FIG. 5(A), a lower-magnification image,
demonstrates uniform sizes of graphene-
enhanced particulates. FIG. 5(B), a higher-
magnification SEM image, clearly shows the
graphene sheets embracing therein primary
particles. FIG. 6 shows an SEM micrograph of
graphene-enhanced tin oxide particulates.
Graphene sheets embrace and protect the primary
particles to form secondary particles
(particulates) that are more uniform in particle
sizes and are larger in average size (˜10 µm) than
the primary particles. These more or less
spherical particles can be easily handled and
made into electrodes using existing battery
electrode coating machines. These particulates
were found to lead to anodes that have a higher
tap density (weight per volume of the electrode),
which is a very important parameter for an
electrode.
One useful class of electrode active material
particles (primary particles) is spherical or
ellipsoidal in shape. For instance, most of the
commercially available Si particles are spherical in
shape. Another useful class of electro-active
material particles is in the form of nanoscopic
wire, also herein referred to as the nanoscopic-
scale wire, nanoscale wire, or nanowire. At any
point along its length, a nanowire has at least one
cross-sectional dimension and, in some
embodiments, two orthogonal cross-sectional
dimensions less than about 500 nm, preferably
less than about 200 nm, more preferably less than
about 100 nm, and most preferably less than
about 50 nm. Where nanoscale wires are
described as having a core and an outer region,
the above dimensions generally relate to those of
the core. The cross-section of the nanoscale wire
may have any arbitrary shape, including, but not
limited to, circular, square, rectangular, tubular, or
elliptical, and may have an irregular shape. For
example, ZnO nanowires have a hexagonal cross-
section, SnO 2 nanowires have a rectangular
cross-section, PbSe nanowires have a square
cross-section, and Si or Ge nanowires have a
circular cross-section. Again, the term “diameter”
is intended to refer to the average of the major
and minor axis of the cross-section. The
nanoscale wire may be solid or hollow. The
length of the nanoscale wire is preferably at least
1 µm and more preferably at least 5 µm. The
wires should have an aspect ratio (length to
diameter) of at least about 2:1 and preferably
greater than about 10:1.
As used herein, a nanotube (e.g. a carbon
nanotube) is generally a nanoscopic wire that is
hollow, or that has a hollowed-out core, including
those nanotubes known to those of ordinary skill
in the art. Nanotubes and nano rods may be
considered as two special classes of small wires
for use as the primary particles that can be
embraced by graphene sheets to form
particulates (secondary particles) in the invention.
Catalytic growth is a powerful tool to form a
variety of wire- or whisker-like structures with
diameters ranging from just a few nanometers to
the micrometer range. A range of phases (gas,
solid, liquid, solution, and supercritical fluid) have
been used for the feeder phase, i.e. the source of
material to be incorporated into the nano-wire.
These material systems include Si nanowires
(SiNW), heterojunctions between SiNW and CNT,
SiO x (a sub-stoichiometric silicon oxide), SiO 2,
Si 1-x Ge x , Ge, AlN, ?-Al 2O 3, oxide-coated B, CNx ,
CdO, CdS, CdSe, CdTe, a-Fe 2O 3 (hematite), e-
Fe 2O 3 and Fe 3O 4 (magnetite), GaAs, GaN,
Ga2O 3,GaP, InAs, InN (hexangular structures),
InP, In2 O 3, In 2Se 3, LiF, SnO 2, ZnO, ZnS, ZnSe,
Mn doped Zn 2SO 4, and ZnTe. These nanowires
can be used as anode active materials.
Likewise, there is essentially no constraint on the
type and nature of the cathode active material
provided the active material can be made into a
fine particle form (e.g., a spherical particle, nano-
wire, nano-fiber, nano-rod, or nano-tube) with a
dimension smaller than 1 µm. For cathode
applications, the electrode active material may
comprise a cathode active material selected from
the group consisting of lithium cobalt oxide,
doped lithium cobalt oxide, lithium nickel oxide,
doped lithium nickel oxide, lithium manganese
oxide, doped lithium manganese oxide, lithium
iron phosphate, lithium manganese phosphate,
lithium vanadium oxide, doped lithium vanadium
oxide, lithium vanadium phosphate, lithium
transition metal phosphate, lithium mixed-metal
phosphates, metal sulfides, metal phosphides,
metal halogenides, and combinations thereof.
As a preferred embodiment, the process of
producing graphene-enhanced particulates
comprises (i) preparing a precursor mixture of
graphene or graphene precursor with an anode
active material or a precursor to the active
material; and (ii) thermally and/or chemically
converting the precursor mixture to the graphene-
enhanced anode particulate. Described in more
detail, the process entails:
(a) dispersing or immersing a laminar graphite
material (e.g., graphite powder) in a mixture of an
intercalant and an oxidant (e.g., concentrated
sulfuric acid and nitric acid, respectively) to
obtain a graphite intercalation compound (GIC) or
graphite oxide (GO);
(b) exposing the resulting GIC or GO to a thermal
shock, preferably in a temperature range of
600-1,100° C. for a short period of time (typically
15 to 60 seconds), to obtain exfoliated graphite or
graphite worms; and
(c) dispersing exfoliated graphite in a liquid (e.g.
water) and mechanically separating individual
nano graphene platelets or sheets from graphite
worms using, for instance, a high-shear mixer or
an ultrasonicator to obtain a graphene or
graphene precursor suspension; or, alternatively,
(d) re-dispersing the exfoliated graphite to a
liquid medium containing an acid (e.g., sulfuric
acid), an oxidizing agent (e.g. nitric acid), or an
organic solvent (e.g., NMP) at a desired
temperature for a duration of time until the
exfoliated graphite is converted into graphene
oxide or graphene dissolved in the liquid medium.
The acid is preferably a weak acid (such as
diluted sulfuric acid) or a more environmentally
benign acid, such as formic acid, acetic acid,
citric acid, carboxylic acid, and combinations
thereof. The exfoliated graphite, when dispersed in
these acids, was gradually dispersed and
essentially dissolved to form a graphene or
graphene oxide solution or suspension. Although
not a required operation, stirring, mechanical
shearing, or ultrasonication can be used to
accelerate the dispersion and dissolution step;
(e) dispersing an anode active material or a
precursor to an anode active material to the
graphene or graphene precursor solution or
suspension prepared in step (c) or step (d) to
obtain a precursor mixture suspension; and
(f) thermally and/or chemically converting the
precursor mixture to the graphene-enhanced
anode particulate.
An optional, but desirable intermediate step
between (e) and (f) involves drying the
suspension to form the precursor mixture in a
solid state. If the precursor mixture contains a
precursor to an anode active material (e.g., Co
(OH) 2 being a precursor to Co3O 4 nano
particles), the mixture will be thermally heated
(sintered) to obtain the particulates that contain
primary Co3 O 4 particles therein (e.g., at 300°
C.). If the precursor mixture contains a precursor
to graphene (e.g. graphene oxide), then the
precursor may be subjected to a chemical or
thermal oxidation. A heat treatment at a
temperature of preferably 500-1,000° C. for 1-2
hours would serve to eliminate a majority of the
oxygen content from the graphene sheets.
The carboxylic acid used in step (d) may be
selected from the group consisting of aromatic
carboxylic acid, aliphatic or cycloaliphatic
carboxylic acid, straight chain or branched chain
carboxylic acid, saturated and unsaturated
monocarboxylic acids, dicarboxylic acids and
polycarboxylic acids that have 1-10 carbon
atoms, alkyl esters thereof, and combinations
thereof. Preferably, the carboxylic acid is selected
from the group consisting of saturated aliphatic
carboxylic acids of the formula H(CH 2) n COOH,
wherein n is a number of from 0 to 5, including
formic, acetic, propionic, butyric, pentanoic, and
hexanoic acids, anydrides thereof, reactive
carboxylic acid derivatives thereof, and
combinations thereof. The most preferred
carboxylic acids are formic acid and acetic acid.
In step (e), particles of a carbon or graphite
material may be added along with the anode
active material particles. Alternatively, the anode
active material particles may be coated with a
thin layer of carbon before they are mixed with
the graphene suspension. For instance, micron-,
sub-micron, or nano-scaled Si nano particles may
be mixed into a solution containing a carbon
precursor (e.g. sugar in water or phenolic resin in
a solvent). The liquid component is then removed
from the resulting mixture suspension or paste to
obtain sugar- or resin-coated Li particles. These
coated particles are then heat-treated at a
temperature of 500-1,000° C. to obtain carbon-
coated particles. These particles are then added
to the graphene solution or suspension.
Hence, another embodiment of the present
invention is a process for preparing the presently
invented graphene-enhanced anode particulate. In
one preferred embodiment, the process comprises:
(a) preparing a precursor mixture of graphene or
graphene precursor with an anode active material
or anode active material precursor; and (b)
thermally and/or chemically converting the
precursor mixture to the graphene-enhanced
anode particulate. The step of preparing a
precursor mixture may comprise preparing a
suspension of graphene or graphene precursor
(e.g. graphene oxide or graphene fluoride) in a
liquid medium and mixing an anode active
material or anode active material precursor in the
suspension to form a multi-component
suspension. The process may further comprise a
step of drying the multi-component suspension to
form the precursor mixture.
The step of drying the multi-component
suspension to form the precursor mixture may be
conducted using a spray-drying, spray-pyrolysis,
fluidized-bed drying procedure, or any step that
involves atomizing or aerosolizing the suspension.
The step of converting may comprise a sintering,
heat-treatment, spray-pyrolysis, or fluidized bed
drying or heating procedure. The step of
converting may comprise a procedure of
chemically or thermally reducing the graphene
precursor to reduce or eliminate oxygen or
fluorine content and other non-carbon elements of
the graphene precursor, which graphene precursor
may contain graphene oxide or graphene fluoride.
Upon conversion, the graphene in the particulate
has an oxygen content typically less than 5% by
weight.
As another preferred embodiment, the process
may begin with the production of a precursor
solution or suspension of pristine graphene (non-
oxidized graphene) directly from graphite
particles, which is followed by the addition of an
anode active material or precursor to the anode
active material to this solution or suspension to
obtain a precursor mixture. The production of a
precursor solution or suspension may include the
following steps:
(a) Preparing a suspension containing pristine
nano graphene platelets (NGPs) dispersed in a
liquid medium using, for instance, direct
ultrasonication (e.g., a process disclosed by us in
U.S. patent application Ser. No. 11/800,728 (May
8, 2007));
(b) Optionally removing some of the liquid from
the suspension;
(c) Adding a desired amount of an anode active
material or a precursor to an anode active
material to obtain a precursor mixture suspension
or solution;
(d) Removing the liquid from the suspension to
obtain a precursor mixture solid; and
(e) Thermally and/or chemically converting the
precursor mixture solid to the graphene-enhanced
anode particulate.
For the preparation of an anode, multiple
graphene-enhanced particulates are mixed with a
binder solution (e.g., PVDF in NMP) to obtain a
slurry or paste. A desired amount of the slurry or
paste is then coated onto a current collector,
allowing the liquid to evaporate and leaving
behind an electrode bonded to a surface of a
current electrode. For examples, particulates
containing Si and graphite particles embraced by
graphene sheets may be added to a solution
containing a solvent (NMP). The resulting paste
may be coated onto a copper foil as a current
collector to form a coating layer of 50-500 µm
thick. By allowing the solvent to vaporize one
obtains a negative electrode (anode) for a
lithium-ion battery.
In the aforementioned examples, the starting
material for the preparation of NGPs is a graphitic
material that may be selected from the group
consisting of natural graphite, artificial graphite,
graphite oxide, graphite fluoride, graphite fiber,
carbon fiber, carbon nano-fiber, carbon nano-
tube, mesophase carbon micro-bead (MCMB) or
carbonaceous micro-sphere (CMS), soft carbon,
hard carbon, and combinations thereof.
Graphite oxide may be prepared by dispersing or
immersing a laminar graphite material (e.g.,
powder of natural flake graphite or synthetic
graphite) in an oxidizing agent, typically a mixture
of an intercalant (e.g., concentrated sulfuric acid)
and an oxidant (e.g., nitric acid, hydrogen
peroxide, sodium perchlorate, potassium
permanganate) at a desired temperature (typically
0-70° C.) for a sufficient length of time (typically
30 minutes to 5 days). In order to reduce the
time required to produce a precursor solution or
suspension, one may choose to oxidize the
graphite to some extent for a shorter period of
time (e.g., 30 minutes) to obtain graphite
intercalation compound (GIC). The GIC particles
are then exposed to a thermal shock, preferably in
a temperature range of 600-1,100° C. for typically
15 to 60 seconds to obtain exfoliated graphite or
graphite worms, which are optionally (but
preferably) subjected to mechanical shearing (e.g.
using a mechanical shearing machine or an
ultrasonicator) to break up the graphite flakes
that constitute a graphite worm. The un-broken
graphite worms or individual graphite flakes are
then re-dispersed in water, acid, or organic
solvent and ultrasonicated to obtain a graphene
polymer solution or suspension.
The pristine graphene material is preferably
produced by one of the following three processes:
(A) Intercalating the graphitic material with a
non-oxidizing agent, followed by a thermal or
chemical exfoliation treatment in a non-oxidizing
environment; (B) Subjecting the graphitic material
to a supercritical fluid environment for inter-
graphene layer penetration and exfoliation; or (C)
Dispersing the graphitic material in a powder form
to an aqueous solution containing a surfactant or
dispersing agent to obtain a suspension and
subjecting the suspension to direct
ultrasonication.
In Procedure (A), a particularly preferred step
comprises (i) intercalating the graphitic material
with a non-oxidizing agent, selected from an
alkali metal (e.g., potassium, sodium, lithium, or
cesium), alkaline earth metal, or an alloy, mixture,
or eutectic of an alkali or alkaline metal; and (ii)
a chemical exfoliation treatment (e.g., by
immersing potassium-intercalated graphite in
ethanol solution).
In Procedure (B), a preferred step comprises
immersing the graphitic material to a supercritical
fluid, such as carbon dioxide (e.g., at temperature
T>31° C. and pressure P>7.4 MPa) and water
(e.g., at T>374° C. and P>22.1 MPa), for a period
of time sufficient for inter-graphene layer
penetration (tentative intercalation). This step is
then followed by a sudden de-pressurization to
exfoliate individual graphene layers. Other suitable
supercritical fluids include methane, ethane,
ethylene, hydrogen peroxide, ozone, water
oxidation (water containing a high concentration
of dissolved oxygen), or a mixture thereof.
In Procedure (C), a preferred step comprises (a)
dispersing particles of a graphitic material in a
liquid medium containing therein a surfactant or
dispersing agent to obtain a suspension or slurry;
and (b) exposing the suspension or slurry to
ultrasonic waves (a process commonly referred to
as ultrasonication) at an energy level for a
sufficient length of time to produce the separated
nano-scaled platelets, which are pristine, non-
oxidized NGPs.
NGPs can be produced with an oxygen content no
greater than 25% by weight, preferably below 20%
by weight, further preferably below 5%. Typically,
the oxygen content is between 5% and 20% by
weight. The oxygen content can be determined
using chemical elemental analysis and/or X-ray
photoelectron spectroscopy (XPS).
The resulting suspension can be converted into
micron-scaled droplets (particulates) using
several approaches. For instance, the suspension
may be aerosolized or atomized to form fine
aerosol particles. Concurrently or subsequently,
the liquid or solvent is removed to form solid
particles that are typically spherical or ellipsoidal
in shape with a diameter or major axis typically
less than 10. This procedure may be executed by
using an aerosol generation, atomization, spray
drying, or inkjet printing apparatus. As an optional
but preferred procedure, the solid particles are
simultaneously or subsequently subjected to a
pyrolysis or carbonization treatment to convert
the organic or polymeric material, if existing, into
a carbon material. The heat treatment of
petroleum or coal-based heavy oil or pitch will
serve to convert at least part of the oil or pitch
into a meso-phase, an optically anisotropic or
liquid crystalline phase of a fused aromatic ring
structure. The converted pitch is called a meso-
phase pitch. Since NGPs are essentially pure
graphite-based or graphene materials, this low
temperature heat treatment (350-1,200° C.) has
no adverse effect on the NGP structure.
Essentially, one can use a spray pyrolysis
technique, such as ultrasonic spray pyrolysis or
electro-spray pyrolysis, to accomplish both the
aerosol generation and pyrolysis procedures
Another embodiment of the present invention is a
lithium ion battery anode comprising multiple
nano graphene-enhanced anode particulates as
described above. A further embodiment is a
lithium ion battery comprising such an anode, a
cathode, a separator disposed between the anode
and the cathode, and electrolyte in physical
contact with both the anode and the cathode.
In a particularly preferred embodiment, a lithium
ion battery may comprise an anode featuring
graphene-enhanced particulates of anode active
particles and a cathode featuring graphene-
enhanced cathode particulates as well. A cathode
particulate is formed of a single graphene sheet
or a plurality of graphene sheets and a plurality of
fine cathode active material particles with a size
smaller than 10 µm (preferably smaller than 1 µm
and more preferably smaller than 100 nm). The
graphene sheets and the particles are mutually
bonded or agglomerated into the cathode
particulate with at least a graphene sheet
embracing the cathode active material particles.
The graphene is in an amount of from 0.01% to
30% by weight based on the cathode particulate
weight. Such graphene-enhanced cathode
particulates may be produced by the processes
similar to those described above for the
production of graphene-enhanced anode
particulates.
There is also no particular restriction on the type
and nature of the cathode active material, which
can be selected for practicing the present
invention. The cathode active material may be
selected from the group consisting of lithium
cobalt oxide, lithium nickel oxide, lithium
manganese oxide, lithium vanadium oxide,
lithium-mixed metal oxide, lithium iron
phosphate, lithium manganese phosphate, lithium
vanadium phosphate, lithium mixed metal
phosphates, metal sulfides, and combinations
thereof.
The positive electrode active material may also
be selected from chalcogen compounds, such as
titanium disulfate or molybdenum disulfate. More
preferred are lithium cobalt oxide (e.g., Lix CoO 2
where 0.8?x?1), lithium nickel oxide (e.g.,
LiNiO2) and lithium manganese oxide (e.g.,
LiMn 2O 4 and LiMnO 2) because these oxides
provide a high cell voltage. Lithium iron
phosphate is also preferred due to its safety
feature and low cost. All these cathode active
substances can be prepared in the form of a fine
powder, nano-wire, nano-rod, nano-fiber, or
nano-tube. They can be readily mixed with NGPs
to form graphene-enhanced particulates.
Acetylene black, carbon black, or ultra-fine
graphite particles may be used as an additional
conductor additive.
For the preparation of a cathode, the binder may
be chosen from polytetrafluoroethylene
(PTFE), polyvinylidene fluoride (PVDF), ethylene-
propylene-diene copolymer (EPDM), or styrene-
butadiene rubber (SBR), for example. Conductive
materials such as electronically conductive
polymers, meso-phase pitch, coal tar pitch, and
petroleum pitch may also be used. Preferable
mixing ratio of these ingredients may be 90 to
98% by weight for the particulates, and 2 to 10%
by weight for the binder. The current collector
may be selected from aluminum foil, stainless
steel foil, and nickel foil. There is no particularly
significant restriction on the type of current
collector, provided the material is a good
electrical conductor and relatively corrosion
resistant. The separator may be selected from a
synthetic resin nonwoven fabric, porous
polyethylene film, porous polypropylene film, or
porous PTFE film.
A wide range of electrolytes can be used for
practicing the instant invention. Most preferred
are non-aqueous and polymer gel electrolytes
although other types can be used. The non-
aqueous electrolyte to be employed herein may be
produced by dissolving an electrolytic salt in a
non-aqueous solvent. Any known non-aqueous
solvent which has been employed as a solvent for
a lithium secondary battery can be employed. A
non-aqueous solvent mainly consisting of a mixed
solvent comprising ethylene carbonate (EC) and
at least one kind of non-aqueous solvent whose
melting point is lower than that of aforementioned
ethylene carbonate and whose donor number is
18 or less (hereinafter referred to as a second
solvent) may be preferably employed. This non-
aqueous solvent is advantageous in that it is (a)
stable against a negative electrode containing a
carbonaceous material well developed in graphite
structure; (b) effective in suppressing the
reductive or oxidative decomposition of
electrolyte; and (c) high in conductivity. A non-
aqueous electrolyte solely composed of ethylene
carbonate (EC) is advantageous in that it is
relatively stable against decomposition through a
reduction by a graphitized carbonaceous material.
However, the melting point of EC is relatively
high, 39 to 40° C., and the viscosity thereof is
relatively high, so that the conductivity thereof is
low, thus making EC alone unsuited for use as a
secondary battery electrolyte to be operated at
room temperature or lower. The second solvent to
be used in a mixture with EC functions to make
the viscosity of the solvent mixture lower than
that of EC alone, thereby promoting the ion
conductivity of the mixed solvent. Furthermore,
when the second solvent having a donor number
of 18 or less (the donor number of ethylene
carbonate is 16.4) is employed, the
aforementioned ethylene carbonate can be easily
and selectively solvated with lithium ion, so that
the reduction reaction of the second solvent with
the carbonaceous material well developed in
graphitization is assumed to be suppressed.
Further, when the donor number of the second
solvent is controlled to not more than 18, the
oxidative decomposition potential to the lithium
electrode can be easily increased to 4 V or more,
so that it is possible to manufacture a lithium
secondary battery of high voltage.
Preferable second solvents are dimethyl carbonate
(DMC), methylethyl carbonate (MEC), diethyl
carbonate (DEC), ethyl propionate, methyl
propionate, propylene carbonate (PC), .gamma.-
butyrolactone (.gamma.-BL), acetonitrile (AN),
ethyl acetate (EA), propyl formate (PF), methyl
formate (MF), toluene, xylene and methyl acetate
(MA). These second solvents may be employed
singly or in a combination of two or more. More
desirably, this second solvent should be selected
from those having a donor number of 16.5 or less.
The viscosity of this second solvent should
preferably be 28 cps or less at 25° C.
The mixing ratio of the aforementioned ethylene
carbonate in the mixed solvent should preferably
be 10 to 80% by volume. If the mixing ratio of the
ethylene carbonate falls outside this range, the
conductivity of the solvent may be lowered or the
solvent tends to be more easily decomposed,
thereby deteriorating the charge/discharge
efficiency. More preferable mixing ratio of the
ethylene carbonate is 20 to 75% by volume. When
the mixing ratio of ethylene carbonate in a non-
aqueous solvent is increased to 20% by volume or
more, the solvating effect of ethylene carbonate
to lithium ions will be facilitated and the solvent
decomposition-inhibiting effect thereof can be
improved.
Examples of preferred mixed solvent are a
composition comprising EC and MEC; comprising
EC, PC and MEC; comprising EC, MEC and DEC;
comprising EC, MEC and DMC; and comprising
EC, MEC, PC and DEC; with the volume ratio of
MEC being controlled within the range of 30 to
80%. By selecting the volume ratio of MEC from
the range of 30 to 80%, more preferably 40 to
70%, the conductivity of the solvent can be
improved. With the purpose of suppressing the
decomposition reaction of the solvent, an
electrolyte having carbon dioxide dissolved therein
may be employed, thereby effectively improving
both the capacity and cycle life of the battery.
The electrolytic salts to be incorporated into a
non-aqueous electrolyte may be selected from a
lithium salt such as lithium perchlorate (LiClO 4 ),
lithium hexafluorophosphate (LiPF 6), lithium
borofluoride (LiBF 4), lithium hexafluoroarsenide
(LiAsF 6), lithium trifluoro-metasulfonate
(LiCF 3SO 3) and bis-trifluoromethyl sulfonylimide
lithium [LiN(CF 3SO 2) 2]. Among them, LiPF 6,
LiBF 4 and LiN(CF 3SO 2) 2 are preferred. The
content of aforementioned electrolytic salts in the
non-aqueous solvent is preferably 0.5 to 2.0 mol/
l.
The following examples serve to illustrate the best
mode practice of the present invention and should
not be construed as limiting the scope of the
invention, which is defined in the claims.
EXAMPLE 1 Graphene Oxide from Sulfuric Acid
Intercalation and Exfoliation of MCMBs
MCMB 2528 meso-carbon microbeads were
supplied by Alumina Trading, which was the U.S.
distributor for the supplier, Osaka Gas Chemical
Company of Japan. This material has a density of
about 2.24 g/cm 3 with a median particle size of
about 22.5. MCMB 2528 (10 grams) were
intercalated with an acid solution (sulfuric acid,
nitric acid, and potassium permanganate at a
ratio of 4:1:0.05) for 48 hours. Upon completion
of the reaction, the mixture was poured into
deionized water and filtered. The intercalated
MCMBs were repeatedly washed in a 5% solution
of HCl to remove most of the sulphate ions. The
sample was then washed repeatedly with
deionized water until the pH of the filtrate was
neutral. The slurry was dried and stored in a
vacuum oven at 60° C. for 24 hours. The dried
powder sample was placed in a quartz tube and
inserted into a horizontal tube furnace pre-set at
a desired temperature, 800° C. for 30 seconds to
obtain Sample 1. A small quantity of each sample
was mixed with water and ultrasonicated at 60-W
power for 10 minutes to obtain a suspension. A
small amount was sampled out, dried, and
investigated with TEM, which indicated that most
of the NGPs were between 1 and 10 layers. The
graphene-water suspension was used for
subsequent preparation of a precursor mixture
containing primary particles of either an anode
active material or a cathode active material.
EXAMPLE 2 Oxidation and Exfoliation of Natural
Graphite
Graphite oxide was prepared by oxidation of
graphite flakes with sulfuric acid, sodium nitrate,
and potassium permanganate at a ratio of
4:1:0.05 at 30° C. for 48 hours, according to the
method of Hummers [U.S. Pat. No. 2,798,878,
Jul. 9, 1957]. Upon completion of the reaction, the
mixture was poured into deionized water and
filtered. The sample was then washed with 5%
HCl solution to remove most of the sulfate ions
and residual salt and then repeatedly rinsed with
deionized water until the pH of the filtrate was
approximately 7. The intent was to remove all
sulfuric and nitric acid residue out of graphite
interstices. The slurry was dried and stored in a
vacuum oven at 60° C. for 24 hours.
The dried, intercalated (oxidized) compound was
exfoliated by placing the sample in a quartz tube
that was inserted into a horizontal tube furnace
pre-set at 1,050° C. to obtain highly exfoliated
graphite. The exfoliated graphite was dispersed in
water along with a 1% surfactant at 45° C. in a
flat-bottomed flask and the resulting graphene
oxide (GO) suspension was subjected to
ultrasonication for a period of 15 minutes.
EXAMPLE 3 Preparation of Graphene-Enhanced
Anode Particulates
For the preparation of graphene-enhanced
particulates, an amount of a selected electrode
active material powder was added to a desired
amount of GO suspension to form a precursor
mixture suspension with a solid content of
approximately 10% by weight. After thorough
mixing in an ultrasonication reactor, the
suspension was then spray-dried to form the
graphene-enhanced particulates.
The anode active materials studied in this
example include Si nano particles, particles of
Co3O 4, Sn, and SnO. The cathode active
materials studied in this example include lithium
cobalt oxide, lithium iron phosphate, and lithium
mixed metal phosphate in a fine particle form.
EXAMPLE 4 Graphene-Enhanced Cobalt Oxide
(Co 3O 4) Anode Particulates Versus Co3O 4-
Coated Graphene Sheets (Prior-Art Layered
Composites)
An appropriate amount of inorganic salts Co
(NO 3 ) 2.6H 2O and, subsequently, ammonia
solution (NH 3 .H2 O, 25 wt %) were slowly added
into a suspension prepared in Example 2. The
resulting precursor suspension was stirred for
several hours under an argon flow to ensure a
complete reaction. The obtained Co(OH) 2/
graphene precursor suspension was divided into
two portions. One portion was filtered and dried
under vacuum at 70° C. to obtain a Co(OH) 2/
graphene composite precursor. This precursor
was calcined at 450° C. in air for 2 h to form the
layered Co3O 4/graphene composites, which are
characterized by having Co3O 4-coated graphene
sheets overlapping one another (schematically
shown in FIG. 7(A)).
The second portion was then atomized and
Just found this on a google search
http://www.motor-fit.de/BATTERIEN-AGM/GEL/Solar/ABAT-Batterien/ABAT-Hochleistungs-AGM-Versorgungs-Batterie-12V-120Ah::42.html
Will ABAT see that $1.00 mark again? I am counting on it.
bet some strong volume comes in next few days
I see that, I tweeted an alert just now
Appears to be heading up still on T/A and something else i am sure .
something for sure going on here, BIG SUPPORT .
Talk of privatization, by Fu and co, buying back shares while this was dark , make any sense???? Thanks
The sector has rallied and ABAT bottomed and traded sideways on the charts. Looks like a technical rally to me
Any reason for uptic? RealDeal? NO Deal?
'Holy Grail of batteries' discovered: Scientists invent pure lithium cells that may mean phones last FOUR times longer
The breakthrough, by engineers from Stanford University, California, could revolutionise technology from electric cars to smartphones
They created the first functioning lithium anode in a lithium battery
Engineers invented a protective film composed of carbon nanosheres to protect the lightweight, conductive material from cracking as it expands
Discovery could lead to consumer electronics with a longer battery life and electric cars with far greater ranges
Read more: http://www.dailymail.co.uk/sciencetech/article-2708675/Holy-Grail-batteries-discovered-Scientists-produce-pure-lithium-cells-mean-phones-FOUR-times-longer.html#ixzz38nr7dryf
Follow us: @MailOnline on Twitter | DailyMail on Facebook
http://www.dailymail.co.uk/sciencetech/article-2708675/Holy-Grail-batteries-discovered-Scientists-produce-pure-lithium-cells-mean-phones-FOUR-times-longer.html
just bid up or buy at ask. thank you .!
gut feeling says some filing news or some chart favors or momentum should be coming outta the gates here soon. just waiting for the carrot !!!
Sounds like you found it, good DD, thanks!!!
Just saw this that might explain
http://m.seekingalpha.com/news/1828585
twitter has changed the game with microcaps...I suggest you get a tweetdeck so you can see when things are being pumped
Takes more than pumpers to move a $2-3 stock like Cbak up 100% in one day on 4.7 million shares in volume imho. Had to be China news, or insider news or believable rumor of a huge vehicle battery contract with CBAK imho and then a spill over to ABAT, or a deal between ABAT and CBAK?
There is no connection. I was using it as an example of trash that is moving big right now. ABAT moved on the heels of the heels of pos CBAK. All the pumpers were calling CBAK the next USU.
I do not see any connection to USU on the ABAT et al, li-ion battery stock rally?
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This board is for fundamental and technical discussion about Advanced Battery Technologies, Inc., GBT.
Founded in September 2002, Advanced Battery Technologies develops, manufactures, and distributes rechargeable PLI battery cells using lithium cobalt oxide anodes to overcome many of the shortcomings associated with other types of rechargeable batteries. GBT develops PLI battery cells for use in electric vehicles, mine lamps, walkie-talkies, and consumer electronics, including cellular telephones, laptop computers, and digital cameras. GBT maintains research and development, and manufacturing facilities in Harbin, China, and administrative offices in New York, New York. Additional information about Advanced Battery Technologies is available at
ABAT Websites: New Web Site: http://www.abatglobal.com
http://www.abatelectricscooter.com/
Check this new page out!!!
http://abat.sys145.pkulab.com/a/English/INVESTORS_/News_from_Green_China/2013/0117/414.html
January 16, 2013 As thick fog and haze shrouded central and northern parts of China over the past several days, with Hebei and Henan provinces among the most polluted areas, monitoring data showed record high levels of particles 2.5 which are various particles of 2.5 microns capable of entering the lungs and bloodstream. Unfortunately, cases requiring medical care increased greatly and there was great concern within China and from concerned parties around the world. At this time, it has become clear that a growing consensus exists among the government and the population that steps must be taken to reduce air pollution. Education and awareness is critical so that new policies can be put in place to reduce this serious problem.
Toward this end, the China Daily has announced a new section of its on-line and in print newspaper entitled "Green China" which will regularly publish special reports to follow Chinese societies' efforts to work toward a more ecologically focussed future. The first issue will be published in March, when the National People's Congress and the Chinese People's Political Consultative Conference (CPCCC) convenes. As a part of the solution to this problem, with its various electric bike and electric scooter models, Advanced Battery Technologies (ABAT) is providing a link to this new section. Together we will be part of the positive shift.
ABAT welcomes verified distributors from numerous countries to contact our representatives to assist you.
Green Transport in China
http://www.chinadaily.com.cn/china/greentransport/
Shanghai Electric Car Incentives
http://www.chinadaily.com.cn/bizchina/greenchina/2013-01/04/content_16092078.htm
http://www.chinadaily.com.cn/bizchina/greenchina/news.htm
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