Constructing a 5.2 V High-Voltage Electrolyte via TMSB Additive Enables Ultrahigh Rate Performance Graphite-Based Dual-Ion Batteries

The development of carbon-based dual-ion batteries (DIBs) is essentially limited by the oxidation decomposition of the electrolyte at high voltage and the unsatisfactory stability of the cathode-electrolyte interface (CEI). Herein, to address these notorious issues, we successfully achieved a high-performance DIB by introducing the Tris(trimethylsiloxy)boron (TMSB) additive. It effectively regulated the solvation structure of the original 2 M LiPF₆-solved EMC electrolyte. As a result, it not only weakens the coordination between the PF₆^- anion and EMC solvent but also suppresses EMC decomposition at the cathode interface. Such regulation facilitates the formation of a stable CEI layer enriched with highly ion-conductive inorganic components. Benefitting from the optimized interfacial kinetics, the graphite cathode delivers exceptional stability and rate capability, achieving 87.86% capacity retention after 2000 cycles at 5.2 V and 84.21% capacity retention at 50 C.