Electrochemical performances and volume variation of nano-textured silicon thin films as anodes for lithium-ion batteries.

Electrochemical behaviors of nano-textured silicon thin film (NTSTF) coated with Al2O3 or Cu layers as anodes for lithium-ion batteries have been investigated. The cyclic performance of NTSTF electrodes is superior to dense Si thin films. The NTSTF with a 5 nm thick Cu coating layer shows superior cyclic performance and rate performance to other NTSTF samples. The volume changes of NTSTF electrodes after the first cycle and the tenth cycle have been investigated. This series of electrodes shows an anisotropic volume variation: the height does not change but the diameter does expand. This finding shows the feasibility of dealing with the vertical expansion and contraction of Si-based powder electrodes in Li-ion batteries.