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.
Nanotechnology To The Rescue
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.” In contrast, the LeydenJar anode is fabricated with a familiar roll-to-roll process that incorporates modded-out plasma-enhanced chemical vapor depositing equipment.
Here’s the explainer from LeydenJar:
“LeydenJar Technologies’ invention is based on a cross-sectoral innovation, applying the production technology of thin film solar panels (and semiconductors) to anode production in a one step approach. We have made a number of alterations to a plasma enhanced chemical vapor depositioning machine (“PECVD”), through which we can control the morphology and porosity of nanostructured Silicon pillars, directly on the copper foil that is used as the anode current collector in the battery industry.”
Next Steps For Next-Gen Energy Storage
Currently, the team is working on a model plant that will be able to churn out 100% silicon anode rolls for battery manufacturers on a test basis. The new plant will also provide a platform for R&D, and it will serve to demonstrate the potential for commercial scale production.
Commissioning is not expected until 2018. In the meantime, LeydenJar is fine tuning its anode and expects to have an optimized version ready for testing by Germany’s nonprofit energy technology institute ZSW next year.
Other researchers have been pursuing the silicon energy storage angle, though it appears that LeydenJar will be first out of the box with a commercial version. Some examples include a silicon anode based on the structure of reed leaves, a composite of silicon and graphine from Korea’s UNIST, silicon “nano-beads” from the University of Maryland, and a pulverized, porous form of silicon from Rice University.
Note: back in 2008, our sister site Gas2.org also took a look at an anode enhanced with a porous form of silicon under development by a team based at Jaephil Cho at Hanyang University in Korea