Tailoring the Electrical Double Layer and Interfacial Electric Field with Diverse Configurational Entropy-Driven Electrolyte for Ultrastable Zinc Metal Anodes

The interfacial stability of zinc anodes depends primarily upon the electrical double layer (EDL) environment and interfacial electric field (IEF) in repeated Zn plating/stripping processes. Herein, a high-entropy electrolyte (HEE) with over 68 types of Zn²⁺ solvation configurations is proposed to modulate the EDL and IEF of Zn anode/electrolyte interface, achieving the improved electrochemical stability and low freezing point. The formation of multiple and water-poor Zn²⁺ solvation configurations facilitates the ion transport dynamics and the desolvation process in the inner Helmholtz plane (IHP), inducing the formation of an organic-inorganic hybrid solid electrolyte interphase (SEI) layer and synergistically guiding the preferential growth of the Zn (100) and (101) crystal planes with compact and dendrite-free deposition morphology. Consequently, the Zn//Cu asymmetric cells with this HEE demonstrate a high average Coulombic efficiency (ACE) of 99.6% for over 3700 cycles (7390 h) at 25 °C and a high ACE of 99.7% for over 4600 cycles (9100 h) at -20 °C. The Zn//Zn symmetric cells also achieve stable operation for more than 3300 and 6900 h at 25 °C and -20 °C, respectively. The Zn//PANI cells exhibit 82.0% capacity retention after 2000 cycles at 1.0 A g^-1 at 25 °C and ∼100% capacity retention after 7000 cycles at 0.5 A g^-1 at -20 °C. This work provides an in-depth insight into the design of HEEs for tailoring the EDL and IEF to enhance the stability of Zn-based batteries.