Effect of pH value on electrochemical property of tin compounds loaded graphite anodes for Li-ion battery applications

A chemical solution method was adopted to prepare Sn compounds loaded graphite anodes with various pH values. When the pH value was 6, multi-phase of Sn compounds were deposited on slices of graphite. The multi-phase compound which contained Sn6O4(OH)4, SnO2, Sn3(PO4)2, and graphite were expected to provide a higher ratio of spectator/Sn for improved cyclability. These phases could be reduced to metallic Sn generating buffer matrix during 1st cycle. The sample pH 6 exhibited the best electrochemical property among all. During cycling between 0.001 and 1.5 V, the 1st charge capacity was around 758 mAh g−1. Even after 50 cycles, the capacity remained higher than 460 mAh g−1. It was demonstrated that multi-phase of Sn compounds loaded graphite anode of sample pH 6 exhibited a better cycling performance than the commercial graphite.