A Three-Functional Zwitterionic Arginine Electrolyte Additive for Modified Zinc Anodes

Abstract

The uncontrolled formation of zinc dendrites and concomitant parasitic reactions at the interface critically undermine the reversibility and operational stability of aqueous zinc electrodes. This study introduces a Zwitterionic polymer-synthesized from C 6 H 14 N 4 O 2 -as an electrolyte additive designed to simultaneously modulate the solvation sheath of Zn 2+ ions, engineer the electrode/electrolyte interfacial double-layer structure, and facilitate in situ formation of a robust, ion-conductive solid electrolyte interphase (SEI) layer on the zinc anode. Consequently, the additive effectively suppresses zinc dendrite growth and mitigates parasitic hydrogen evolution. C 6 H 14 N 4 O 2 preferentially adsorbs onto the active sites associated with zinc corrosion and hydrogen evolution, thereby effectively inhibiting these side reactions. Furthermore, the adsorbed C 6 H 14 N 4 O 2 redistributes the Zn 2+ ion flux, facilitates the desolvation of [Zn(H 2 O) 6 ] 2+ , and promotes uniform zinc deposition under low overpotentials. Consequently, long-term cycling stability with minimal voltage hysteresis (>2900 h at 1 mA cm -2 and 1 mAh cm -2 ) was achieved in Zn||Zn symmetric cells. When paired with a polyaniline (PANI) cathode, the assembled PANI||Zn battery with the addition of C 6 H 14 N 4 O 2 exhibited a capacity of 142.83 mAh g -1 after 1500 cycles, achieving a capacity retention rate of 85.9%. In contrast, the Zn||PANI full cell using pure ZnSO 4 electrolyte demonstrated a capacity of 95.14 mAh g -1 and a capacity retention rate of 77.9%. These results highlight the environmentally friendly of C 6 H 14 N 4 O 2 as an ideal electrolyte additive in aqueous Zinc-ion batteries.