Attainment of high rate capability of Si film as the anode of Li-ion batteries

In an attempt to improve the high power capability of the Li insertion/extraction reaction of a vacuum deposited Si film on a Ni foil, we tried to increase the electron conductivity of the deposited film by sandwiching a metal conducting film of Cu and Ag with the Si film. The metal-sandwiched film showed the rate to be improved over 1.5 times as compared a single layer deposited film. The second trial for improving the rate was to use a carrier doped Si having a high conductivity. Deposition of 5 Omega cm Si film on a Ni foil resulted in an attainment of not only the high power capability over with 30 C rate but also the cycle life over 3000 cycles. The issue to be solved was to attain the capability with a very thick deposited film.