Electrochemical performance of ball-milled ZnO–SnO2 systems as anodes in lithium-ion battery

ZnO displays similar redox and alloying chemistry to the tin oxides on Li insertion. It might, therefore, be expected to be an interesting network modifier for tin oxides. ZnO/SnO2 composites show degradation in cycling performance, however, for low ZnO levels, cyclability is improved by some milling, however, for high ZnO levels milling degrades performance, probably due to the increase of ZnO activity. On testing ZnO, it is found that it cycles very poorly. Both electrochemical and X-ray studies indicate that highly crystalline LixZn alloys are formed. It seems that the high degree of crystallisation on insertion is the determinant factor leading to the poor performance of ZnO and ZnO/SnO2 composites compared to SnO2.