Tin(Sn) and its alloys have been attracting attentions as a negative electrode
material for sodium-ion secondary batteries with high theoretical capacity
(Na15Sn4, ca. 847 mAh/g) and high
electromotiveforce. There still remains the issue as regards the discharge
capacity decrease with increasing the number of cycles. In order to improve
cycle performance, there are many studies such as using Sn-Ni alloy, however,
using Sn based alloy as negative electrode materials and it suffer from the
disadvantage of lowering of discharge capacity. In this study, a deposition
process for making Sn film which consists of amorphous structure for negative
electrode of sodium ion secondary batteries utilizing electordeposition from
aqueous bath was developed. The effect of additives on the surface morphology
and microstructure of Sn film was investigated. Furthermore, we evaluated the
effect of amorphous structure in the Sn film on cycle performance of the Sn
negative electrode. Sn film has a good cycle characteristic (>50
cycles) and discharge capacity (> 400 mAh/g). Amorphous structure in
the Sn film showed a microscopic effect on the volume change by sodiation and
desodiation.