Eco-friendly in-situ electrospun PLA/ZnO-ZnF₂ biomass composite separator enabling stable zinc anode for sustainable aqueous batteries

Aqueous zinc-ion batteries (AZIBs) are promising energy storage devices due to their inherent safety and environmental benignity, yet dendrite formation and parasitic side reactions severely hinder their commercialization. While prevailing strategies employing organic composite layers or electrolyte additives could enhance anode stability, they inevitably introduce non-degradable pollutants. An eco-friendly in-situ electrospun biodegradable separator is proposed, consisting of polylactic acid (PLA) functionalized with a ZnO-ZnF₂ heterostructure and hydrophilic polyvinylpyrrolidone (POFP). This composite separator implements a strategy of guided ion deposition on specific crystal surfaces”, synergistically homogenizing Zn²⁺ flux through the high ionic conductivity of ZnO, while ZnF₂ facilitates robust solid-electrolyte interphase formation. Consequently, the POFP-modified Zn anode achieves exceptional cyclic durability over 1500 h in symmetric cells, along with 500 reversible Zn||Cu plating/stripping cycles at 1 mA cm⁻². When paired with an I₂@AC cathode, the full cell retains 94.98 % capacity retention after 2000 cycles at 5 A g⁻¹, outperforming >90 % of previously reported AZIBs under comparable cycling conditions. This work pioneer's biomass-derived functional separators, offering a sustainable pathway toward high-performance, eco-friendly aqueous zinc batteries.