Flexible hydrogel compound of V2O5/GO/PVA for enhancing mechanical and zinc storage performances

A highly flexible hydrogel cathode applied in rechargeable aqueous zinc-ion batteries (ZIBs) fabricated by polyvinyl alcohol (PVA), vanadium pentoxide (V 2 O 5 ) and graphene oxide (GO) has been successfully synthesized by repeated freeze-thaw method. The V 2 O 5 /GO hydrogel (VOGH) presented complex 3D cross-linking system and excellent flexibility through hydrogen bonding and inorganic nanosheets reinforcement. The mechanical and electrochemical properties of VOGH are balanced and achieved by adjusting the content of GO (5%), V 2 O 5 (30%), PVA (25%) and water (40%) of the total mass, respectively. From the electrochemical result, the flexible hydrogel cathode displayed a high capacity (240.5 mA h g –1 ) and a good cyclic stability after 200 cycles at 1 A g –1 . Moreover, the electrochemical kinetics exhibite the capacitive control process, which confirm the excellent ion transport to enhance storage performance of ZIBs. The soft package ZIBs using VOGH as cathode and Zn foil as anode display good cycle performance (191.7 mA h g –1 at 1 A g –1 after 1000 cycles) and provide stable power supply at different bending angles.