In Situ Integrating Highly Ionic Conductive LDH-Array@PVA Gel Electrolyte and MXene/Zn Anode for Dendrite-Free High-Performance Flexible Zn–Air Batteries

摘要

Low interfacial ion transfer kinetics and structure instability of solid-state electrolytesare the bottleneck which seriously limits the working life and energydensity of flexible zinc–air batteries (ZABs). Herein, an optimized electrode–electrolyte integrated MXene/Zn-layered double hydroxides (LDH)-array@PVA structure is developed via an electrochemical Zn deposition, in situ LDHgrowth, polymer infiltration, and crosslinking route, integrating anode andgel polymer electrolyte (GPE) for high-performance flexible ZABs. The highlyorientated hydrophilic CoNi-LDH arrays sufficiently crosslink with poly(vinylalcohol) (PVA) chains, which effectively decreases the crystallinity degree ofthe PVA polymer and provides fast ionic diffusion channels to reduce theionic transport barrier, endowing LDH-array@PVA GPE with significantlyimproved ionic conductivity, water retention capability, and mechanical flexibility.Moreover, the optimized anode-GPE integrated interface of MXene/Zn-LDH-array@PVA demonstrates excellent interfacial compatibility and stability,effectively reduces the interfacial impedance, and promotes the interfacialionic transfer kinetics, enhancing a uniform zinc deposition without dendriteformation. The optimized ionic transfer kinetics and stable anode-GPEintegrated interface bring the MXene/Zn-LDH-array@PVA-based flexible ZABa long cycling life up to 50 h, and a high power density of 92.3 mW cm~(?2). Therationally designed in situ crosslinking and integration strategies provideenlightening pathways for the design of high-performance flexible ZABs.