Electrochemical Role of Transition Metals in Sn–Fe Alloy Revealed by Operando Magnetometry

• Published in: Chinese physics letters Vol. 39; no. 2; pp. 28202 - 后插2
• Main Authors: Zhang, Le-Qing, Xia, Qing-Tao, Li, Zhao-Hui, Han, Yuan-Yuan, Xu, Xi-Xiang, Zhao, Xin-Long, Wang, Xia, Pan, Yuan-Yuan, Li, Hong-Sen, Li, Qiang
• Format: Journal Article
• Language: English
• Published: Chinese Physical Society and IOP Publishing Ltd 01.02.2022; College of Physics,Qingdao University,Qingdao 266071,China%College of Physics,Qingdao University,Qingdao 266071,China; Weihai Innovation Institute,Qingdao University,Weihai 264200,China
• ISSN: 0256-307X; 1741-3540
• DOI: 10.1088/0256-307X/39/2/028202

As promising materials, alloy-type anode materials have been intensively investigated in both academia and industry. To release huge volume expansion during alloying/dealloying process, they are usually doped with transition metals. However, the electrochemical role of transition metals has not been fully understood. Here, pure Sn 3 Fe films were deposited by sputtering, and the electrochemical mechanism was systematically investigated by operando magnetometry. We confirmed that Fe particles liberated by Li insertion recombine partially with Sn during the delithiation, while the stepwise increase in magnetization with the cycles demonstrates growth of Fe nanoparticles. In addition, we also found an unconventional increase of magnetization in the charging process, which can be attributed to the space charge storage at the interface of Fe/Li x Sn. These critical findings pave the way for the mechanism understanding and development of high-performance Sn based alloy electrode materials.