In situ Diffuse Reflectance Spectroelectrochemistry of Cathode Materials in Lithium-ion Batteries
Developing in situ spectroelectrochemistry methods,which can provide detailed information about species trans-formation during electrochemical reactions,is very important for studying electrode reaction mechanisms and improving battery performance.Studying real-time changes in the surface of electrode materials during normal operation can be an effective way to assess and optimize the practical performance of electrode materials,thus,in situ and in operando characterization techniques are particularly important.However,batteries are hard to be studied by in situ characterization measurements due to their hermetically sealed shells,and there is still much room for battery characterizations.In this work,a specially designed battery based on the structure of coin cells,whose upper cover was transparent,was constructed.With such a device,acquisition of diffuse reflectance spectra of electrode materials during charging and discharging was realized.This not only provided a simple measurement accessory for diffuse reflectance spectroscopy(DRS),but also complemented in situ characterization techniques for batteries.Taking commonly used cathode materials in lithium-ion batteries(LIBs),including LiFePO4(LFP),NCM811 and LiCoO2(LCO)as examples,we managed to find out the response relationships of different electrode materials to visible light of different wavelengths under ordinary reflectance illumination conditions.Heterogeneity of different cathode ma-terials on interaction relationships with the lights of different wavelengths was also revealed.This work demonstrated the capability of guiding wavelength selection for different materials and assessing electrochemical performances of in situ diffuse reflectance spectroelectrochemistry.By combining electrochemistry with diffuse reflectance spectroscopy,this work made an effective complementary for spectroelectrochemistry.
Lithium-ion batteryDiffuse reflectance spectroelectrochemistryIn situCathode material
陈露露、李浩冉、刘维祎、王伟
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生命分析化学国家重点实验室,南京大学化学化工学院,江苏南京 210023
锂离子电池 漫反射光谱电化学 原位 正极材料
National Natural Science Foundation of ChinaExcellent Research Program of Nanjing University