Rational Electrode Design for Enhanced Battery Performance: Addressing SOC Heterogeneity and Achieving Energy Density

The heterogeneity in the state of charge (SOC) across electrodes can significantly abbreviate battery lifespan, deteriorate safety metrics, and diminish capability rate. Despite being a known issue for some time, the factors contributing to this phenomenon have not been systematically summarized. Without a thorough understanding of the underlying causes, it is difficult to devise preventive strategies that can effectively enhance electrode behavior. This paper provides a comprehensive analysis of the factors inducing electrode SOC heterogeneity, identifying the unequal distribution of ions and electrons as the primary cause of the varied reaction rates across the electrode, which ultimately leads to SOC heterogeneity. Subsequently, preventive measures are outlined with a focus on electrode composition and structure. Furthermore, implications of SOC heterogeneity and the challenges associated with achieving both large power density and high energy density in electrodes are discussed. A more profound grasp of the mechanisms governing ion and electron conduction, coupled with materials that can resolve these dilemmas into win–win outcomes, is essential for the advancement of electrodes.