A Dutch startup called LeydenJar is boldly going where no one else in the energy storage field has apparently gone before. The company, a spinoff from the Energy Research Centre of the Netherlands, has come up with a new version of lithium-ion battery technology that uses 100% silicon instead of graphite.
At first glance, that’s a risky proposition, because normally silicon goes through destructive cycles of shrinkage and expansion when used in rechargeable batteries. However, if the new battery can be manufactured at scale with a reasonable lifespan, the payoff is an increase in capacity of up to 50% over conventional graphite-based energy storage.
With an all-silicon recipe, the LeydenJar team claims that it has increased the capacity of the anode in its new lithium-ion battery by a factor of 10.
They managed to do that without ending up with crumbled bits of battery on the floor by applying a one-machine, plasma-based fabrication method to the anode.
The silicon is deposited onto a copper substrate in nanoscale columns, achieving a height of about 10 microns (that’s the thickness required for commercial application, according to LeydenJar).
The resulting pattern of filled and empty spaces provides enough room for the silicon to expand safely when the battery is recharged.
Yet Another Happy Accident
The team also drew on lessons learned from failed experiments in the solar field. The silicon column approach dates back at least a dozen years, when researchers at the Energy Research Centre were trying to develop the material for use in solar cells.
That didn’t work out as planned, but all that effort was not lost since the technology has been transferred to the energy storage field.
The new battery’s ties to the solar field also carry over to the manufacturing process.
The plasma-based method enables commercial-scale production of what was previously possible only in small batches. As described by LeydenJar, there is a huge difference between their one-machine, one-step process and conventional anode production.
Conventional graphite anodes can be enhanced with small amounts of silicon, but that requires “active material, binder, and other components in a capital-intensive process consisting of slurry making, a coating process, a baking process, calendering and slitting.”
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