Effect of carrier gas on anode performance of Si thick-film electrodes prepared by gas-deposition method

Silicon thick-film electrodes for Li-ion battery anodes were prepared by a gas-deposition method using carrier gases of Ar and He. We investigated the effect of the carrier gases on film morphology and anode performance. The root mean square roughness of the films formed by He gas was twice larger than that formed by Ar gas. The Si electrode obtained by He gas exhibited a larger film thickness up to 4 mm, a higher initial capacity of 2280 mA h g-1, and larger capacities until 40th cycle compared with other electrodes. The better performance is probably attributed to a formation of many interspaces within the thick film. It is suggested that these interspaces enhanced contact area between active material and electrolyte, which enabled an efficient alloying/dealloying reaction of Li–Si.