Biomimetic Anchor-Capture Effect of Multidentate Electrolyte Additive for Ultrastable Aqueous Zinc Ion Batteries

Uncontrolled dendrite growth and hydrogen evolution reactions on Zn anodes severely limit the practical application of aqueous zinc-ion batteries. Electrolyte additive engineering offers a promising solution. This work proposes a bio-inspired anchor-capture effect using the multi-dentate additive to simultaneously achieve robust interface construction and rapid Zn²⁺ capture. Stevia (ST), a natural biomass extract featuring flexible multi-dentate hydrophilic chain and rigid skeleton is selected as a proof of concept. Systematic characterizations and theoretical calculations verify the anchor-capture effect of ST as trace electrolyte additive. On one hand, ST molecules preferentially adsorb and accumulate on the Zn anode surface, promoting the formation of homogeneous electrode-electrolyte-interface layer and reconstructing the interfacial hydrogen bonding network. On the other hand, the flexible multi-dentate hydrophilic chains enhance the capture and immobilization of Zn²⁺, suppressing the 2D diffusion and guiding uniform deposition. Additionally, the strong binding energy between Zn²⁺ and ST facilitates the desolvation process. As a result, Zn||Zn symmetrical cells exhibit an ultra-long cycle lifespan (>8800 h at 0.5 mA cm^-2), Zn||Cu asymmetrical cells perform exceptional reversibility (the average coulombic efficiency > 99.5% over 1200 cycles) and Zn||VO₂ full cells retain almost 100% capacity over 1000 cycles at 2 A g^-1. The biomimetic interface engineering strategy provides valuable insights for developing green electrolyte additives to stabilize Zn anodes.