Researchers at the Institute for Chemistry & Technology of Materials at TU Graz have developed a new method that utilizes silicon for a lithium-ion battery. Its storage capacity is 10 times higher than the graphite substrate which has been used in batteries until now, and promises considerable improvements for battery users.

The new findings – which came to light in the NanoPoliBat EU project – have been recently submitted as a patent application by the TU Graz researchers, together with their cooperation partner Varta Microbattery.

In the new battery fabrication process, researchers apply a silicon-containing gel to the graphite substrate material. ‘In this way the graphite works as a buffer, cushioning the big changes in volume of the silicon during the uptake and transfer of lithium ions,’ explains battery researcher and PhD student Stefan Koller.

Silicon has a lithium-ion storage capacity some 10 times higher than commercially used graphite in batteries. The new material can thus store more than double the number of lithium ions, without changes to the battery lifetime.

This battery fabrication method is far cheaper than the previous ones in which silicon is separated in the gas phase. The challenge lies in the poor storage density of materials in the counter-electrode in the whole battery, on which Koller and his colleagues have been doing intensive research.