Ribavirin as a Dual-Function Electrolyte Additive for Dendrite-Free Zinc-Ion Batteries through Surface Adsorption and Coordination Structure Disruption

The unregulated zinc dendrite formation, together with undesirable parasitic side reactions, has posed major obstacles to the commercialization and stability of aqueous zinc-ion batteries (AZIBs). Herein, as an additive in the electrolyte of AZIBs with dual functions, ribavirin, a small molecule antiviral drug, was innovatively employed to tackle these issues. Simulation and experimental findings consistently revealed that the incorporation of ribavirin effectively suppressed the formation of zinc dendrites and markedly enhanced the stability of the reaction system. Ribavirin disrupted the stable coordination structure of the ZnSO₄ electrolyte. Mediated by hydrophilic interactions from its hydroxyl groups, ribavirin decreased the number of water molecules within the solvation shell, which in turn enhanced the dynamic freedom of zinc ions and adjacent water molecules, thereby markedly promoting zinc-ion diffusion during battery operation. Additionally, ribavirin molecules preferentially adsorbed onto the zinc sheet surface, forming a protective layer that not only effectively mitigated the corrosive effects of the ZnSO₄ electrolyte but also facilitated electron transfer and inhibited the hydrogen evolution reaction (HER). Moreover, the introduction of ribavirin into the ZnSO₄ electrolyte facilitated three-dimensional (3D) ion diffusion, leading to a smoother zinc deposition process and a remarkable suppression of zinc dendrite growth during battery cycling. Benefiting from this dual function of coordination regulation and surface adsorption, the Zn//Cu asymmetric cells with ribavirin maintained consistent performance over 1000 charge/discharge cycles, still exhibiting a stable Coulombic efficiency of 98.6% at the 950th cycle, while the Zn//Zn symmetric cells demonstrated exceptionally stable cycling for over 2800 h at 1 mA·cm^-2 and over 1050 h at 2 mA·cm^-2, concurrently delivering enhanced Coulombic efficiency and superior rate performance. Furthermore, in V₂O₅-based full cells, ribavirin enhanced zinc-ion transport, improved specific capacity, and enabled stable cycling for over 2000 cycles.