Selective Proton Acceleration Channel via Gradient Built-in Electric Field Strategy for High-performance Zinc-ion Batteries

In the emerging energy storage mechanism of Zn²⁺ and proton (H⁺) co-embedding in aqueous zinc ion batteries (ZIBs), H⁺ with minimal molar mass and fast (un)coordination kinetics significantly alleviate the structural strain to boost the cycling stability. Yet, existing storage mechanisms make the high percentage of proton storage limited. Here, an entropy-modulated gradient built-in electric field strategy is employed to construct selective proton transport channels and provide proton immobilization sites to enhance proton storage. Through experimental and theoretical analyses of materials with different entropy values, the unique charge characteristics of high-entropy materials resulting in the gradient built-in electric fields inside the materials to form a continuous ion transport pathway are demonstrated. Compared with Zn²⁺, H⁺ with high charge-to-mass ratio and low transport energy barrier enable more continuous and rapid ion transport in the accelerated channel to selectively modulate the H⁺ transport kinetics. Additionally, the multiple active centers of the gradient built-in electric field serve as immobilizers for proton embedding, which markedly enhances the binding capacity of protons in the material. These findings provide insight into the essential function of the entropy-regulated gradient built-in electric field mechanism for proton-selective storage, and provide a new reference for developing high-performance ZIBs.