Enthalpy-Entropy Modulation in Electrolyte Stabilizes 4.8 V-Class Li-Rich Mn-Based Cathodes
Yuhao Ma1, Shihong Qing1, Hongyu Liu1
1School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu, China.
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.
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