Separators for Rechargeable Alkaline Zinc Batteries: Challenges and Progress

Abstract Separator membrane is an essential element within every battery system, having a significant influence on both safety and electrochemical performance. With rejuvenated interest in rechargeable alkaline zinc batteries, such as zinc-air, nickel-zinc (NiZn), and zinc-manganese (Zn-MnO2) batteries, there has been an increased focus on scrutinizing the role of each component in the battery system, including the separator. This scrutiny arises from the realization that separator properties are vital for influencing battery cycle life, discharge capacity, rate capability, and capacity retention. Various types of separators have been thoroughly investigated for their suitability in rechargeable alkaline zinc batteries, including nonwoven, microporous, inorganic, and polymer electrolyte membranes. Primary challenges associated with rechargeable alkaline zinc batteries are zincate ion crossover and dendrite penetration of the separator, both of which are known to adversely affect the battery performance and safety. Significant efforts have been dedicated to modifying conventional membranes, as well as to develop new separators tailored to address the challenges encountered by these battery systems. This review provides comprehensive overview on the challenges in development of alkaline zinc batteries, different types of separators utilized in rechargeable alkaline zinc batteries, and the optimization strategies employed to enhance battery performance.