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 LiPF 6 -solved EMC electrolyte. As a result, it not only weakens the coordination between the PF 6 – 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.