Decoupling Zn²⁺/H⁺ Transport via Polysaccharide Molecular Traps for Stable Zn Anode

Abstract Zn metal anodes face chronic challenges from dendrite growth and hydrogen evolution reactions (HER), severely limiting their practical application. Theories centered on Zn²⁺ transport behavior have dominated explanations for the high performance of Zn anode coatings, while neglecting the effect of H⁺. Here, a polysaccharide molecular trapping strategy is proposed to stabilize Zn anodes by decoupling Zn²⁺ and H⁺ transport kinetics. The moderate trapping of Zn²⁺ guides uniform deposition by suppressing lateral migration, while the strong trapping of H⁺ selectively restricts its transport, shifting the HER rate‐determining step to proton diffusion. Consequently, vanadium‐based full cell with XG@Zn anode works steadily at high‐loading cathode, thin anode, and lean electrolyte with almost no capacity fade. The combined advantages of facile fabrication and exceptional electrochemical performance underscore its commercial viability. This work establishes cation differentiation trapping as a universal design principle for Zn anode engineering, providing critical insights for next‐generation Zn metal batteries.