A Nature‐Inspired Separator with Water‐Confined and Kinetics‐Boosted Effects for Sustainable and High‐Utilization Zn Metal Batteries

Abstract Uncontrollable dendrite growth and sluggish ion‐transport kinetics are considered as the main obstacles for the further development of high‐performance aqueous zinc ion batteries (AZIBs). Here, a nature‐inspired separator (ZnHAP/BC) is developed to tackle these issues via the hybridization of the biomass‐derived bacterial cellulose (BC) network and nano‐hydroxyapatite particles (HAP). The as‐prepared ZnHAP/BC separator not only regulates the desolvation process of the hydrated Zn 2+ ions (Zn(H 2 O) 6 2+ ) by suppressing the water reactivity through the surface functional groups, alleviating the water‐induced side‐reactions, but also boosts the ion‐transport kinetics and homogenize the Zn 2+ flux, resulting in a fast and uniform Zn deposition. Remarkably, the Zn|Zn symmetric cell with ZnHAP/BC separator harvests a long‐term stability over 1600 h at 1 mA cm −2 , 1 mAh cm −2 and endures stable cycling over 1025 and 611 h even at a high depth of discharge (DOD) of 50% and 80%, respectively. The Zn|V 2 O 5 full cell with a low negative/positive (N/P) capacity ratio of 2.7 achieves a superior capacity retention of 82% after 2500 cycles at 10 A g −1 . Furthermore, the Zn/HAP separator can be totally degraded within 2 weeks. This work develops a novel nature‐derived separator and provides insights in constructing functional separators toward sustainable and advanced AZIBs.