Entropy-driven disordered solvation sheath configurations for high voltage aqueous electrolytes

Zinc-ion capacitors (ZICs), combining high energy and power density, are regarded as promising alternatives for next generation energy storage system. However, their development is hindered by the narrow electrochemical stability window (ESW) of aqueous electrolytes. Herein, inspired by high entropy alloys and Molecular dynamics simulation, a novel high entropy disordered aqueous electrolyte incorporating five co-solvents is developed, with the unexpected discovery that the entropy effects play a critical role in the reconstruction of the solvation sheath structure, exhibiting 181 configurations without any single dominant species, achieving a remarkably wide ESW of 5.285 V. The highly disordered distribution of these configurations, as evidenced by the reduced hydrogen bond density, substantially disrupts the hydrogen bonding network and suppresses the decomposition of water molecules. Furthermore, the reduced Zn²⁺ migration energy barrier suppresses dendrite growth, as confirmed by differential electrochemical mass spectrometry (DEMS). Utilizing this high-entropy electrolyte, the symmetric cell demonstrates stable cycling for 2750 h, and high voltage ZICs achieve a remarkable energy density of 48.62 W h kg^‐1 with a Coulombic efficiency approaching 100%. The high-entropy strategy proposed in this work presents a feasible pathway for the development of high-voltage aqueous electrolytes. © 2025 Elsevier B.V.