A silicon dominant lithium-ion battery with less than 1% cell expansion has been developed by materials company E-magy and German research institute ZSW (Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg).
E-magy’s nano-porous silicon, used as the active anode material, absorbs the expansion in the nano structure itself to enable a 0.9% overall cell expansion.
Silicon’s tendency to expand and break during charging and discharging has been the main barrier to industry adoption.
The Netherlands-based firm advocates the use of silicon-dominant anodes, whereby 80% or more of the material in the anode is silicon.
To examine the volume expansion of the material, silicon-dominant anodes were paired with NMC cathodes to build bi-layer pouch cells.
The pouch cells were placed in custom-made cell holders for dilatometric measurements and subjected to 100 charge/discharge cycles to enable the monitoring of thickness variation during cycling.
The successful buffering of the anode swelling at material level was further validated using post-mortem electron microscope cross-section analysis.
The research was published in the peer-reviewed Journal of The Electrochemical Society.
Casper Peeters, CEO of E-magy, said: “Taming silicon is the first major breakthrough in battery technology since the commercial introduction of graphite-based Li-ion cells in the early 90’s.
“Although battery technology has come a long way, improvements have been incremental and slower than what consumers need. With silicon-dominant anodes becoming a reality, we will see a whole slew of new product categories that have simply not been possible until now.”