Enhancing Precision and Durability of Built-In Cu-Li Reference Electrodes in Lithium-Ion Batteries: A Critical Review

The reference electrode (RE), integrated as a sensor within lithium-ion batteries (LIBs), offers real-time insights into the electrochemical properties of individual electrodes, which makes it an ideal indicator for monitoring the working state of LIBs. Nevertheless, most built-in REs in LIBs face significant challenges that limit their application as precise and durable sensors for effective battery management, relegating them to being rough and temporary indicators in research settings. This Review delves into the latest advances in enhancing the accuracy and longevity of lithium metal deposited on Cu (Cu-Li) REs. It explores the underlying causes and factors contributing to measurement inaccuracies. Finally, the Review puts forth strategies to overcome these challenges in three-electrode LIBs. Gaining a comprehensive understanding of the intrinsic behaviors of LIBs, REs, and their interactions is pivotal for developing high-precision REs, thereby accelerating the innovation of new and safer LIB technologies.