Solvation configuration and interfacial chemistry regulation via a bio-based Cyrene additive for highly reversible zinc anodes

Abstract

The unstable anode–electrolyte interface caused by water-induced parasitic reactions and rampant dendrite growth severely hampers the practical deployment of aqueous zinc batteries. Herein, a bio-based Cyrene solvent is used as a dual-function electrolyte additive to improve the reversibility of zinc metal anodes. Theoretical and experimental analyses verify that Cyrene molecules can synergistically modulate the solvation configuration of Zn²⁺ and the interfacial microenvironment. The water molecules released from the solvation shell of Zn²⁺ and the regulated ion associations of SO₄²⁻ restrain water decomposition activity and passivation byproduct formation. Simultaneously, Cyrene molecules are adsorbed preferentially on the surface of the zinc anode, which induces orientation sedimentation of Zn²⁺ and inhibits the detrimental dendrite growth. Consequently, the symmetric cell with the Cyrene additive provides high plating/stripping reversibility of over 2000 cycles at 5 mA cm⁻², and the MnO₂-based full cell exhibits improved stability compared to the additive-free counterpart.