Biomass-based electrolyte design for aqueous zinc-ion batteries: Recent advances and future outlook

Aqueous zinc-ion battery (AZIB) has attracted broad attention to date owing to the high capacity and economic efficiency. Nevertheless, critical bottlenecks related to the anode side impede its further development. The employment of aqueous electrolytes ensures good safety and ionic conductivity, it would otherwise trigger numerous side reactions. Moreover, uneven Zn plating/stripping at the anode side might induce catastrophic dendritic growth. Addressing these issues through a rational electrolyte design holds promise in improving battery stability. Biomass materials, featured by diverse architecture, enriched surface chemistry and appealing eco-friendliness, offer a potential countermeasure to develop high-performance AZIBs. In this review, the state-of-the-art research advances in electrolyte design based on biomass materials are covered, accompanied by detailed elucidation of underlying mechanisms. In addition, current challenges and future outlook for the application-driven design of biomass-based electrolytes are proposed.