I think Hyzon Motors are a few steps ahead, in the fuel cell stack design game. above 132 kW rated power 3.6 kW/L power density -30 °C cold start capability 20,000h lifetime. This is the rating for most fuel stacks is 3 kW/L (per liter)
Hyzon new 200kW fuel cell stack is 6 kW/LHyzon Motors 200kW - ready for production 2024.