Dutch cleantech startup E-magy and German research institute ZSW have demonstrated silicon-anode lithium-ion batteries that expand and contract less than 1 percent upon charging and discharging. The battery industry considers less than 10 percent acceptable. The results have been published in the Journal of the Electrochemical Society.
As silicon can host more lithium ions per unit volume than graphite, it offers significant increases in battery energy density. There’s one problem, though: it tends to expand and crack during charging and discharging. E-magy is one of several companies working on nanostructured silicon that’s able to more comfortably accommodate lithium guests.
“Taming silicon is the first major breakthrough in battery technology since the commercial introduction of graphite-based Li-ion cells in the early 90s. 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’ll see a whole slew of new product categories that have simply not been possible until now,” comments Casper Peeters, CEO of E-magy.
The company advocates the use of silicon-dominant anodes, ie anodes in which 80+ percent or more of the material in the anode is silicon. With this composition, batteries will gain an estimated 40 percent increase in energy density compared to conventional graphite anodes.