Revealing interfacial space charge storage of Li+/Na+/K+ by operando magnetometry

Xiangkun Li; Jie Su; Zhaohui Li; Zhiqiang Zhao; Fengling Zhang; Leqing Zhang; Wanneng Ye; Qinghao Li; Kai Wang; Xia Wang; Hongsen Li; Han Hu; Shishen Yan; Guo-Xing Miao; Qiang Li

doi:10.1016/j.scib.2022.04.001

Revealing interfacial space charge storage of Li⁺/Na⁺/K⁺ by operando magnetometry

Sci Bull (Beijing). 2022 Jun 15;67(11):1145-1153. doi: 10.1016/j.scib.2022.04.001. Epub 2022 Apr 3.

Authors

Xiangkun Li¹, Jie Su¹, Zhaohui Li¹, Zhiqiang Zhao¹, Fengling Zhang¹, Leqing Zhang¹, Wanneng Ye¹, Qinghao Li¹, Kai Wang¹, Xia Wang¹, Hongsen Li¹, Han Hu², Shishen Yan³, Guo-Xing Miao⁴, Qiang Li⁵

Affiliations

¹ College of Physics, University-Industry Joint Center for Ocean Observation and Broadband Communication, State Key Laboratory of Bio-Fibers and Eco-Textiles, Weihai Innovation Research Institute, Qingdao University, Qingdao 266071, China.
² State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering, China University of Petroleum (East China), Qingdao 266580, China.
³ School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China.
⁴ Department of Electrical and Computer Engineering & Institute for Quantum Computing, University of Waterloo, Ontario N2L 3G1, Canada.
⁵ College of Physics, University-Industry Joint Center for Ocean Observation and Broadband Communication, State Key Laboratory of Bio-Fibers and Eco-Textiles, Weihai Innovation Research Institute, Qingdao University, Qingdao 266071, China. Electronic address: liqiang@qdu.edu.cn.

PMID: 36545981
DOI: 10.1016/j.scib.2022.04.001

Abstract

Interfacial space charge storage between ionic and electronic conductor is a promising scheme to further improve energy and power density of alkali metal ion batteries (AMIBs). However, the general behavior of space charge storage in AMIBs has been less investigated experimentally, mostly due to the complicated electrochemical behavior and lack of proper characterization techniques. Here, we use operando magnetometry to verify that in FeSe₂ AMIBs, abundant Li⁺/Na⁺/K⁺ (M⁺) can be stored at M₂Se phase while electrons accumulate at Fe nanoparticles, forming interfacial space charge layers. Magnetic and dynamics tests further demonstrate that with increasing ionic radius from Li⁺, Na⁺ to K⁺, the reaction kinetics can be hindered, resulting in limited Fe formation and reduced space charge storage capacity. This work lays solid foundation for studying the complex interfacial effect in electrochemical processes and designing advanced energy storage devices with substantial capacity and considerable power density.

Keywords: Alkali metal ions batteries; FeSe(2); Interfacial space charge storage; Kinetics; Operando magnetometry.