Full‐Lifecycle Monitoring of Electrode States in Lithium‐Ion Batteries

Abstract The evolution of various side reactions at a single electrode gives rise to the complex degradation behavior of lithium‐ion batteries (LIBs), necessitating strategies to decouple and track the states of each electrode. Electrode potential sensors (EPSs) are the dedicated tool for monitoring electrode states, however, their limited cycle life (up to 300 cycles) compared to LIBs (≈2000 cycles) hampers their long‐term application. Here, a systematic method is proposed for full‐lifecycle monitoring of electrode‐state evolution. It is identified that electrochemical dissolution and deposition during cycling lead to continuous, irreversible lithium loss, which drives the rapid degradation of traditional Li‐type EPSs. To mitigate this, an intercalation‐type EPS framework is designed that suppresses irreversible lithium loss to below 20%. However, reversible lithium loss still accumulates over time, causing EPS signal drift. To address this, drift correction and secondary activation techniques are introduced to rejuvenate intercalation‐type EPSs after reversible degradation, significantly enhancing the stability and extending their service life beyond 1800 cycles—over six times longer than the current state‐of‐the‐art. This work delivers a foundational tool for tracking electrode states over the full lifecycle of LIBs, paving the way for electrode management and control in next‐generation smart batteries.