3D Oxygen-Defective Potassium Vanadate/Carbon Nanoribbon Networks as High-Performance Cathodes for Aqueous Zinc-Ion Batteries

Rechargeable aqueous zinc-ion batteries (ZIBs) have attracted extensive interest owing to their low cost and high safety. Herein, oxygen-defective potassium vanadate/amorphous carbon nanoribbons (C-KVO vertical bar O-d) are successfully synthesized through a one-step solid-state sintering process as a high-performance cathode material for ZIBs. This unique 3D interconnected network structure can not only act as a continuous conductive path but also decrease aggregation and provide more adsorption sites for zinc ions. The as-prepared C-KVO vertical bar O-d exhibits a high capacity of 385 mAh g(-1) at 0.2 A g(-1), superior rate performance (166 mAh g(-1) even at 20 A g(-1)), and an outstanding cycling stability with a 95% capacity retention over 1000 cycles. Density functional theory calculations elucidate that the oxygen defects in the C-KVO vertical bar O-d remarkably reduce the Zn2+ ion's adsorption Gibbs free energy and Zn2+-diffusion barriers. Meanwhile, the amorphous carbon networks enable the rapid electron transfer and provide additional active sites for Zn2+ storage. This work can facilitate the development of high-performance ZIBs for large-scale energy storage.