Degradation mechanism of tin phosphide as Na-ion battery negative electrode

• 作者: Hiroki Sakaguchi Hiroyuki Usui Ryota Yamagami Yasuhiro Domi
• 来源期刊: 绿色能源与环境:英文版
• 学科: 工学
• 关键词: TIN phosphide(Sn4P3) Ionic liquid ELECTROLYTE Na-ion BATTERY Negative electrode material NANOSTRUCTURE
• 年，卷（期）: 2019,（2）
• 页码范围: 121-126
• 页数: 6页
• 分类号: TK

摘要

The degradation mechanism of an Sn4P3 electrode as Na-ion battery anode was investigated by using a transmission electron microscopic observation.At the first desodiation,we confirmed that Sn nanoparticles with 6 nm in size were dispersed in an amorphous-like P matrix.Compared to this,we observed aggregated Sn particles with sizes exceeding 50 nm after the drastic capacity fading.The capacity fading mechanism was for the first time confirmed to be Sn aggregation.To improve the capacity decay,we carried out the two kinds of charge-discharge cycling tests under the reduced volume changes of Sn particles and P matrix by limiting desodiation reactions of NaeSn and Na3P,respectively.The Sn4P3 electrode exhibited an excellent cyclability with the discharge capacity of 500 mA h g-1 for 420 cycles under the limited desodiation,whereas the capacity decay was accelerated under the limited sodiation.The results suggest that the Sn aggregation can be improved by the reduced volume change of the P matrix,and that it is very effective for improving anode performance of Sn4P3 electrode.