Molecular Damping Effect of Trace Additives Enhances Zinc Anode Stability Under High Depth of Discharge.

Abstract

Resolving the severe issues such as electric field distortion, dendritic zinc growth, and uneven zinc deposition under high depths of discharge (DOD) has become a significant hurdle of the aqueous zinc-ion batteries (ZIBs). To address these challenges, an interfacial regulation strategy is proposed based on the molecular damping effect, in which a trace amount of weakly adsorbing additive is employed to stabilize the Zn anode interface by mitigating energy shocks and ionic disturbances induced by electric field fluctuations. Trace perfluorinated PSVE (erfluoro-3,6-dioxa-4-methyloct-7-enesulphonyl fluoride) is introduced to the traditional ZnSO₄ electrolyte to optimize Zn deposition behavior on the zinc anode. Thus, the Zn//Zn symmetric batteries exhibit a prolonged cycling lifespan of over 200 h, even when operated at a high DOD of 85.5%. Additionally, the NVO (Na₂V₆O₁₆) cathodes coupled with Zn anodes and modified electrolyte present a more stable capacity retention, maintaining a capacity of 141.98 mAh g^-1 after 1000 cycles. Similarly, the full batteries assembled with the same electrodes in a ZnSO₄ electrolyte retain only 51.49 mAh g^-1 capacity after the same conditions. This work highlights the potential of the molecular damping effect as a promising solution for improving high DOD performance in ZIBs.