Functional Natural Aluminum Silicate Hydroxide Based Separators Enable Stable Zinc Metal Anodes with Long Cycle Life

Abstract Benefiting from high safety, low cost, and competitive energy density, aqueous zinc ion batteries (AZIBs) have emerged as very promising technology for grid energy storage. However, the lifetime of AZIBs is severely affected by uncontrolled zinc dendritic growth and undesirable side reaction. To address the problem, natural aluminum silicate hydroxide covered glass fibers separator (AlSi‐GF) is prepared herein using a simple spraying method. Aluminum silicate hydroxide is a complex oxide, where a large number of adsorption sites can adsorb Zn 2+ and guide its deposition process. In particular, the Maxwell–Wagner polarization of aluminum silicate hydroxide under an applied electric field contributes to homogenizing the electric field distribution around the interface, thereby modulating zinc deposition and reducing the nucleation overpotential. Impressively, AlSi‐GF separator enables high‐performance zinc‐metal batteries. The symmetric battery with AlSi‐GF separator has a stable voltage polarization and an ultra‐long cycle life of 2280 h at a current density of 1 mA cm −2 , and the Zn//V 2 O 5 full cell based on AlSi‐GF separator can exhibit a high specific capacity of 123 mAh g −1 after 1500 cycles at 1 A g −1 . This study provides new insights into the design of reliable and cost‐effective separators for metal anodes in energy storage devices.