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

Abstract

AbstractRechargeable 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|Od) 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|Od 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|Od 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.