Electrochemical behavior of SiO as an anode material for Na-ion battery

Electrochemical behavior of SiO electrode as a Na-ion battery anode was investigated by using thick-film electrodes without any binder or conductive additive. The SiO electrode reacted with Na to exhibit a reversible capacity of over 200 mA h g−1 at the first cycle, whereas Si electrode showed less capacity. We previously demonstrated that SiO being an amorphous material is composed of three-dimensional SiO4 tetrahedral network similar to silica glass and Si clusters, and that the Si clusters are finely dispersed in the SiO4 matrices. Given this characteristics, it is considered that the capacity obtained from the SiO originates from an alloying reaction of the Si clusters having a high surface energy with Na.