电化学储能电池正极界面反应活性的扫描电化学显微镜原位分析

In-situ Investigation of Interfacial Electrochemical Reactivity by Scanning Electrochemical Microscopy

设计、构建了用于扫描电化学显微镜原位检测Li^+/Na^+电池及室温液态金属电池反应过程的电解池,成功用于电池正极界面反应动力学检测。测得氧化还原电介质二茂铁在LiFePO4、Li Co O2和Na3V2(PO4)3三种不同正极界面反应电子转移速率常数(kf)分别为1.06×10^-3cm/s、1.47×10^-3cm/s和9.09×10^-4cm/s。实时监测了三种不同碳含量Na3V2(PO4)3正极界面微区(80×80μm2)储钠活性位点分布,探索了室温Li||Ga电池液态金属正极界面锂化反应过程。表明基于扫描电化学显微镜技术的原位电池分析方法具有极高的分辨率和灵敏度,且对不同电池体系均可实现实时原位高分辨动力学检测。为研究Li^+/Na^+电池及液态金属电池等极具应用潜力的电化学储能技术提供了一种原位无损检测方法。

An electrochemical cell has been designed to realise sodium/lithium ion battery and Li||Ga liquid metal battery inside glove box filled with argon for in-situ scanning electrochemical microscopy(SECM)analysis.The heterogenous rate constant of electron transfer(k f)of ferrocenium/ferrocene at three different cathodes of commercial LiFePO 4&LiCoO 2,and self-prepared Na 3V 2(PO 4)3 have been measured to be 1.06×10-3 cm/s,1.47×10-3 cm/s and 9.09×10-4 cm/s,respectively.The electrochemical sodium storage activity of Na 3V 2(PO 4)3/C cathode/electrolyte interface has been monitored when battery is working.The reversible lithiation process of gallium liquid metal cathode is recorded.All the results provide useful electrochemical information for further understanding of interfacial mechanism of cathode.This non-interference,non-destructive and in-situ analysis method based on SECM could be a practical choice for battery analysis.