A bifunctional biomass-derived additive for constructing a hybrid SEI layer to enhance the cycling stability of aqueous zinc-ion batteries under high current densities

Abstract

Employing biomass-derived additives for electrolyte modulation constitutes an effective and highly promising strategy to address the core challenges of aqueous zinc-ion batteries (AZIBs). Although existing biomass-derived additives combine environmental benignity with cost-effectiveness, they remain constrained by challenges in terms of long-term cycling stability compatible with high current densities. Herein, we proposed the utilization of biomass-derived ferulic acid (FA) as an additive to fabricate a bifunctional aqueous electrolyte, which enhanced the electrochemical performance of AZIBs through coordination regulation and surface adsorption. Theoretical calculations revealed that FA modulated the Zn²⁺ solvation structure, preferentially adsorbed on the Zn (002) plane, weakened the Zn²⁺–H₂O interaction, and inhibited the hydrogen evolution reaction (HER). Electrochemical measurements confirmed that the Zn//Zn symmetric cell exhibited stable cycling for 4000 h at 0.5 mA cm⁻² (0.5 mAh cm⁻²) and 1400 h at 10 mA cm⁻² (10 mAh cm⁻²). The Zn//Cu half-cell achieved a high coulombic efficiency (CE) of 99.53% after 2000 cycles at 5 mA cm⁻², whereas the Zn//P-NVO full cell retained 85.6% of its initial capacity after 1000 cycles at 2 A g⁻¹. This green and low-cost strategy provides a feasible route toward the industrialization of AZIBs.