Cellulose-based separators in aqueous zinc-ion batteries: Mechanistic strategies for dendrite suppression and...

As global renewable energy demand increases, the development of advanced energy storage systems is critical. Aqueous zinc-ion batteries (AZIBs) exhibit great potential due to their safety, cost-effectiveness, and environmental sustainability. Nonetheless, the formation and growth of zinc dendrites remain a major hurdle challenge, severely restricting the AZIBs' practical applications. This review explores the critical function of cellulose-based separators in mitigating the formation and growth of zinc dendrites. Four core mechanisms underlying the dendrite-suppressing efficacy by cellulose-based separators have been summarized: 1) ‌Mechanical resistance: the inherent strength and flexibility of cellulose physically impede dendrite penetration; 2) zb flux homogenization: achieved via uniform pore distribution, electric field regulation, and selective ion transport; 3) Directed planar zinc deposition: guided by preferential (002) crystalline orientation of zinc to prevent vertical dendrite growth; 4) Alter in dendrite growth direction: functionalized separators promote "counter-deposition", altering the growth pathway. Furthermore, this review consolidates recent advances in diverse cellulose-based materials, highlighting their structure-property correlations and electrochemical performance in AZIBs. Finally, existing challenges and propose future directions for the development of high-performance cellulose-based separators are discussed, aiming to pave the way for their widespread commercial adoption.