A Toolbox of Reference Electrodes for Lithium Batteries

Electrochemical energy storage systems play an increasingly important role in our daily lives. The detection/estimation of the state of electrochemical cells is therefore a prerequisite for the development of safe, high-performance batteries. Reference electrodes (REs) are an effective tool for monitoring the status of batteries and are of critical significance in this field. However, the practical construction of a durable RE for long-term research and industrial applications is still challenging. In this article, the fundamental principles of a three-electrode system featuring the presence of REs are elucidated. The design parameters of REs in lithium batteries, including active materials, manufacturing, geometry, and placement, are comprehensively summarized, and the typical applications of REs in practical lithium-ion batteries to facilitate working/failure mechanism analysis and methods to monitor Li plating are analyzed. Finally, the challenges and future trends of the exploitation and deployment of REs in lithium batteries are presented.