银/氯化银参比电极漏电流情况下的失效机理

Failure Mechanism of Ag/AgCl Reference Electrode Due to Current Leakage

采用热浸涂-电化学还原方法制备了Ag/AgCl参比电极,通过加速极化试验方法研究了电极失效过程及机理。采用扫描电子显微镜(SEM)、能谱仪(EDX)和电化学阻抗(EIS)测试手段研究了电极失效过程中表面状态、形貌及性能的变化。结果表明,Ag/AgCl参比电极失效后电极电位出现大幅波动,电极表面呈疏松多孔结构,AgCl完全转化为银,Ag/AgCl参比电极在漏电流情况下失效的主要原因是电极中AgCl被还原为银所致。

A Ag/AgCl reference electrode was prepared by thermal-dip coating followed by electrochemical reduction. The failure mechanism of the electrode was studied by accelerated polarization method. The microstructure and performance of the electrode were analyzed by scanning electron microscopy（SEM）, energy dispersed ？（ray spectroscopy（EDX）, and electrochemical impedance spectroscopy（EIS）. After the acceleration test, the potential of the Ag/AgCI reference electrode fluctuated grjeatly, and the electrode surface showed a morphology of porous structure. EDX results indicate that AgCl transformed into Ag completely on the electrode surface. So, the failure of Ag/AgCl reference electrode could be attributed to the complete transformation of AgCl into Ag.