Thin film a-Si based nano in micro complex structured anodes for high-performance lithium-ion secondary batteries

The nano in micro complex structure is formed by wet etching, which is a simple, fast, and costeffective process. Thin-film a-Si-based anodes are fabricated by depositing a-Si on a nano in micro complex structured Ni foam current collector, which is performed by low-pressure chemical vapor deposition (LPCVD). Ni foams are then used as current collectors to increase the contact area between the active materials and current collector. This leads to an increase in the loading densities of the active materials. The nano in micro complex structured surface has large surface area with voids, which not only accommodate the volume changes during cycling, but also enhance adhesion between the active materials and current collector. As a result, after 190 cycles, a cell with etched Ni foam anode shows about 10% higher discharge capacity compare to a cell with Ni foil anode.