PVA-assisted construction of cathode-electrolyte interface pre-desolvation strategy realizes high-performance flexible aqueous zinc ion batteries.

Due to the solvated structure of Zn2+, a large amount of bound water is released during (de)intercalation to impact the lattice of the electrode material and aggravate the dissolution of vanadium actives, which seriously restricts the practical application of vanadium-based cathodes. Herein, a cathode-electrolyte interface pre-desolvation structure is constructed using polyvinyl alcohol (PVA) in this study. The solvation structure of Zn2+ is regulated through the confinement effect of polymer chains, significantly lowering the desolvation energy barrier, thereby mitigating lattice damage to the electrode material and dissolution of active substances. Moreover, three-dimensional porous conductive network constructed by combining carbon nanotubes (CNT) and flame-reduced graphene oxide (FRGO) effectively enhances the electrode conductivity and ion migration rate. The flexible electrode (PNVO@CG) constructed by effectively integrating NH4V4O10 (NVO) with the substrate exhibits excellent rate performance and cycle stability, which remains a capacity of 428.1 mAh/g after 140 cycles at 0.5 A/g and 208.8 mAh/g after 4000 cycles at 15 A/g. In particular, the flexible PNVO@CG thin film battery has a maximum specific capacity of 396.7 mAh/g and maintains an excellent capacity stability during bending for 180°. Further integration of flexible pack cells with solar panels offers the possibility of renewable energy storage. This study provides a new opportunity of cathodes for the long-lifespan and flexible wearable ZIBs.