Pre-potassiated hydrated vanadium oxide as cathode for quasi-solid-state zinc-ion battery

Zinc-ion batteries(ZIBs),in particular quasi-solid-state ZIBs,occupy a crucial position in the field of energy storage devices owing to the superiorities of abundant zinc reserve,low cost,high safety and high theoretical capacity of zinc anode.However,as divalent Zn^(2+)ions experience strong electrostatic interactions when intercalating into the cathode materials,which poses challenges to the structural stability and higher demand in Zn^(2+)ions diffusion kinetics of the cathode materials.Here,a microwave-assisted hydrothermal method is adopted to prepare pre-potassiated hydrated vanadium pentoxide(K_(0.52)V_(2)O_(5)·0.29H_(2)O,abbreviated as KHVO)cathode material,in which the potassium ions preinserted into the interlayers can act as“pillars”to stabilize the lamellar structure,and crystal water can act as“lubricant”to improve the diffusion efficiency of Zn^(2+)ions.Consequently,the KHVO displays high electrochemical properties with high capacity(∼300 mAh/g),superior rate capability(69 mAh/g at 5 A/g)and ultralong cycling performance(>1500 cycles at 2 A/g)in quasi-solid-state ZIBs.These superior Zn storage properties result from the large diffusion coefficient and highly stable and reversible Zn^(2+)(de)intercalation reaction of KHVO.