BTRY, a Swiss cleantech company founded in 2023, develops innovative monolithically-stacked solid-state lithium-ion batteries based on thin-film technology. BTRY's solid-state batteries can be recharged within one minute. They last longer and are safer than conventional lithium-ion batteries. They can operate in extreme temperatures. This makes them suitable for a wide range of applications.
Challenges: solid-state lithium-ion battery
Solid-state lithium-ion batteries are getting a lot of attention because they are safer and have the potential to offer much higher energy density than conventional lithium-ion batteries.
Solid-state lithium-ion batteries use a solid-state electrolyte, which is less likely to catch fire compared to the flammable liquid electrolytes used in conventional lithium-ion batteries. This significantly reduces the risk of battery fires, making solid-state batteries a safer option.
Solid-state lithium-ion batteries use lithium metal as the anode, which has a much higher theoretical capacity than the graphite anodes used in traditional lithium-ion batteries. Higher energy density means more energy can be stored in the same volume, which is particularly important for applications like drones, robots, and electric vertical take-off and landing aircraft (eVTOL).
Currently, lithium metal foil is deposited through physical vapor deposition (PVD). Lithium metal foil as anode, on the other hand, is hard to use because it forms a passivating film on the surface even in a dry room. To keep it from becoming passivated, it should be handled in an argon atmosphere. This makes solid-state lithium-ion batteries harder to manufacture than conventional lithium-ion batteries.
Anode-free solid-state batteries don’t use an anode in the manufacturing process. Even with this benefit, the uneven growth of lithium metal occurs at the interface between the anode current collector and the solid-state electrolyte, which is still a big problem.
Current solid-state lithium-ion batteries often use significantly thicker separators (i.e., solid-state electrolytes) than conventional lithium-ion batteries with organic liquid electrolytes. Therefore, the specific energy and power of solid-state lithium-ion batteries lag behind.
BTRY develops monolithically stacked thin-film solid-state lithium-ion batteries. The battery consists of at least two monolithically stacked thin-film cells. Each cell consists of a seed layer, a solid-oxide electrolyte, and a lithium cobalt oxide cathode. The stacked thin-film batteries can achieve specific energies >250 Wh kg⁻¹ at C-rates above 60, resulting in a specific power of tens of kW kg⁻¹. This means that the monolithically stacked thin-film cells have the potential to increase the power tenfold. BTRY’s technology meets needs of high-end applications such as drones, robots, and electric vertical take-off and landing aircraft.
BTRY solid-state battery
The diagram below depicts BTRY’s anode-free monolithically stacked thin-film batteries with two stacked cells (cell 1 and cell 2) in series connection.
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