Silicon anodes to boost lithium-ion battery capacity within a few years
The main impediment to mass electric-car adoption is price, and the driving force behind that is the cost of lithium-ion battery cells.
The performance of those cells improves at about 7 percent a year, give or take: Either the same cell costs 7 percent less after a year, or a carmaker gets 7 percent more energy capacity for the same price.
Those improvements come from a combination of economies of scale, tweaks to the battery chemistry, fabrication improvements, and higher yields.
Now, however, battery engineers suggest that more of a step change may arrive by 2020 to 2022—potentially double-digit increases in the energy storage capacity of individual cells.
The new developments were summarized Sunday by The Wall Street Journal (subscription may be required). What was pure laboratory research five years ago is now moving closer to production.
The "secret sauce" is the use of anodes made from silicon, rather than the graphite (essentially crystalline carbon) used almost across the board in today's cells.
Of the two electrodes in every cell, the anode is the one that discharges lithium ions that travel through the electrolyte and are absorbed into the cathode. Charging the cell reverses the process.
Theoretically, silicon could absorb and hold many times the number of lithium ions that carbon can, but limiting that process to prevent destruction of the anode is just one of the many technical challenges to making such cells practical.
Today's graphite anodes blend small amounts of silicon into the carbon to boost range, but most likely 10 percent or less.
The Wall Street Journal piece focuses on several startup companies that claim to be close to production-ready cells with anodes largely made from silicon. Among them are Angstron Materials , Enovix, Enevate, and Sila Nanotechnologies.
Using nanoparticles to ensure the cells have plenty of space for lithium ions to be absorbed without swelling or shattering the anode, those makers claim capacity increases of 20 to 40 percent over the best comparable graphite-anode cells. (BSRC has this, and better {100% improvement, double the range of a Tesla}, NOW, and has partnered with Ferroglobe. From the Ferroglobe PR: This joint agreement follows BioSolar’s recent announcement that it has achieved a significant performance milestone in silicon micro-particle (SiMP) anodes enhanced by its innovative silicon anode additive technology, with data suggesting its technology can achieve significantly higher capacity with lowered costs. Through this partnership, as well as other potential industry relationships, Ferroglobe seeks to capitalize upon what many consider to be a high growth market opportunity, as recent reports predict the silicon anode battery market will hit a CAGR of 21.5% through 2024.
With its proprietary technology relating to silicon anode material for lithium ion batteries, BioSolar believes Ferroglobe is a natural fit as a developmental partner. As the global leader in the supply of silicon materials, Ferroglobe possesses experience in incorporating technologies such as BioSolar’s silicon additive technology into its own raw silicon materials.
“We are excited to partner with BioSolar, a company whose technology represents tremendous upside in the development of lithium-ion batteries with respect to capacity, efficiency and safety,” said Benoist Ollivier, EVP-Technology at Ferroglobe. “We continue to focus on the development of high value added advanced materials, and are confident that our focus on silicon anode material development will yield results that ultimately reduce costs and improve output.”
“We are pleased to have Ferroglobe as a development partner, a company with a proven track record of developing and supplying silicon materials to global marketplaces,” said Dr. David Lee, CEO of BioSolar. “We are confident that this partnership and its subsequent results will continue to demonstrate not only higher performance but also better price points, strengthening BioSolar’s commercial viability and market potential.”)
Now being tested around the world by dozens of potential customers, these so-called lithium-silicon cells will appear first in small versions used in high-end consumer electronics devices.
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