Enthalpy‐Entropy Modulation in Electrolyte Stabilizes 4.8 V‐Class Li‐Rich Mn‐Based Cathodes

ABSTRACT Lithium‐rich manganese‐based (LRM) cathode materials are promising for high‐energy‐density batteries due to their high specific capacity. However, their high operating voltage (4.8 V vs. Li/Li + ) compromises cycling stability in conventional carbonate‐based electrolytes. Here, we design a rational “enthalpy‐entropy modulation” strategy for electrolytes, guided by thermodynamic parameters. By weakening ion‐solvent interactions to enhance anion involvement (enthalpy modulation), while amplifying disorder to increase configurational diversity (entropy modulation), we reconfigure the solvation sheath from a solvent‐dominated state to an anion‐involved, diversified configuration. This reconfiguration facilitates lithium‐ion desolvation and suppresses free solvent decomposition, fostering a stable cathode‐electrolyte interphase. Consequently, the LRM cathode delivers extended cycle life (400 cycles, 76.6% retention at 1C), outstanding fast‐charging capability (1068 cycles at 3C with 1.4 mg cm −2 ), and stable cycling under high mass loading of 20.1 mg cm −2 (0.2C). This work demonstrates a thermodynamically guided approach for developing the next generation of electrolytes for high‐voltage LRM cathodes.