Biomass-based separators for aqueous zinc-ion batteries: advantages, strategies, and perspectives

Abstract

Aqueous zinc-ion batteries (ZIBs) have emerged as a promising candidate for large-scale energy storage owing to their intrinsic safety, low cost, and environmental friendliness.Currently, ZIBs have achieved significant advancements in core components such as cathode, anode, and electrolyte, whereas research progress on separator materials remains comparatively limited. The separator, as a crucial component of ZIBs, plays a crucial role in preventing internal electrical short circuits and facilitating ion transport. Biomass-based separators (e.g., cellulose, chitosan, chitin, and lignin) offer eco-friendly advantages by utilizing renewable resources with tunable microstructures and abundant functional groups, enabling enhanced wettability, mechanical strength, and dendrite suppression, thereby improving battery safety and performance. In this review, we summarize the recent advances of biomass-based separators for application in aqueous ZIBs. We begin with a comprehensive overview of ZIBs separators and their fundamental requirements. Then, we systematically analyze representative biomass-based separators for ZIBs, focusing on their structural configurations, preparation methods, modification strategies, and operational mechanisms (including regulating the uniform Zn deposition, inhibiting the Zn dendrites growth, and avoiding side reactions). Finally, the remaining challenges and promising perspectives of biomass-based separators for ZIBs are outlined, providing helpful guidance for their further development in large-scale applications.