Qiu Xiangyun, Hua Qingsong, Zheng Lili, Dai Zuoqiang
Power & Energy Storage System Research Center, School of Mechanical and Electrical Engineering, Qingdao University No. 308 Ningxia Road Qingdao 266071 P. R. China
National Engineering Research Center for Intelligent Electrical Vehicle Power System (Qingdao) No. 308 Ningxia Road Qingdao 266071 P. R. China.
RSC Adv. 2020 Feb 3;10(9):5283-5293. doi: 10.1039/c9ra10527a. eCollection 2020 Jan 29.
Electrochemical impedance spectroscopy (EIS) was used to study the initial discharge/charge process in a sulfur cathode with different potentials. In the second discharge region (2.00-1.70 V), where soluble polysulfides are reduced to LiS, the EIS spectra exhibit three semicircles/arcs as the frequency decreased. An appropriate equivalent circuit is proposed to fit the experimental EIS data. Based on detailed analysis of the change in kinetic parameters obtained from simulating the experimental EIS data as functions of potential, the high-frequency, middle-frequency and low-frequency semicircles/arcs can be attributed to the Schottky contact reflecting the electronic properties of materials, the charge transfer step and the formation of LiS respectively. The inclined line arises from the diffusion process in the detectable potentials and frequency range. Several important electrochemical reactions also have been verified by cyclic voltammetry curves.
采用电化学阻抗谱（EIS）研究了不同电位下硫正极的初始充放电过程。在第二个放电区域（2.00 - 1.70 V），可溶性多硫化物在此区域还原为LiS，随着频率降低，EIS谱图呈现出三个半圆/弧。提出了一个合适的等效电路来拟合实验EIS数据。通过详细分析模拟实验EIS数据得到的动力学参数随电位的变化，高频、中频和低频半圆/弧分别可归因于反映材料电子性质的肖特基接触、电荷转移步骤和LiS的形成。斜线源于可检测电位和频率范围内的扩散过程。循环伏安曲线也验证了几个重要的电化学反应。
