LeydenJar Technologies, a Dutch spin-out of the applied research institute TNO, has developed a new,100% silicon anode for lithium-ion batteries. This breakthrough offers two key benefits: batteries with a 70% higher energy density (1350 Wh/L) and 62% less CO2 emissions.
The anode is ready for production and LeydenJar is preparing to scale-up its production capacity in the coming years.
The new technology does not push up production costs and is a plug-in solution to existing battery gigafactories. A 70% higher energy density will have an impact on various sectors: consumer electronics, electric vehicles and the storage of renewable energy.
As an anode material, silicon has ten times the capacity of carbon. However, so far, it has only been possible to produce anodes with a small amount of silicon, because the anodes were mainly carbon-based; the use of silicon was hampered by the mechanical limitations of the material.
LeydenJar’s pure silicon anode is porous, allowing it to absorb the swelling of the silicon during lithation, and thus uses the maximum capacity of silicon, while remaining mechanically stable. The silicon is grown directly on the copper substrate with plasma vapor deposition (PECVD), a method used in the PV and semiconductor industry to grow thin films.
LeydenJar altered this process to grow silicon columns that lead to high anode area loading, enabling energy density up to 1.200 Wh/l or 450 Wh/kg at lithiated stack level.
The pure silicon anodes are produced in a single process step on a roll-to-roll PECVD machine, located at the High Tech Campus in Eindhoven, the Netherlands.
Tested pouch cells were built using commercially available battery materials, such as NMC 622 cathodes, and LeydenJar’s silicon anodes. An energy density of 1350 Wh/L at start of battery life was reached, with these cells demonstrating a cycle life of more than 100 cycles at a C/2 rate.
DNV GL has confirmed these results. Looking forward, LeydenJar’s CTO, Yiseop Ahn, expects to be able to significantly improve the cycle life performance.