Bridging thermodynamics and ion transport in lithium batteries via molecular design of high-entropy electrolytes

Abstract

Although high-entropy electrolytes are promising for stabilizing lithium metal batteries, the intrinsic correlation between thermodynamic entropy and ion transport remains elusive. Herein, we propose a multi-anion electrolyte with elevated solvation-configurational entropy (S_sc) and excess entropy (S_ex), which successfully breaks the solubility limit of LiNO₃ (reaching 0.1 M) in carbonate solvents. This high-entropy environment thermodynamically reshapes the solvation structure, weakening solvent coordination and enhancing anion participation. Based on molecular dynamics simulations, we demonstrate that the Li⁺ self-diffusion coefficient follows the classical Rosenfeld scaling relationship with S_ex, establishing a scaling relationship to describe ion transport in complex electrolytes. Experimentally, this strategy facilitates a compact, inorganic-rich SEI/CEI, enabling a high coulombic efficiency of 99.2%, an expanded oxidation window (>4.7 V), and remarkable capacity retention (>86.1% after 400 cycles) in Li||NCM811 full cells. This work establishes a quantitative entropy-based framework for electrolyte design, bridging the gap between microscopic disorder and macroscopic battery performance.