J. Cao, D.D. Zhang, Y.L. Yue, X. Wang, T. Pakornchote, T. Bovornratanaraks, X.Y. Zhang*, Z.-S. Wu*, J.Q. Qin*

Nano Energy, 2021, 84, 105876.

DOI: 10.1016/j.nanoen.2021.105876 [PDF]

Aqueous zinc-ion batteries (ZIBs) are recognized asa promising class of electrochemical energy storage devices due to their high safety and low cost, however, rational design of high-performance cathodes with stable internal structures and fast Zn²⁺diffusion channels remains challenging. Herein, we reported an advanced cathode ofoxygen defect enriched (NH₄)₂V₁₀O₂₅•8H₂O (NVO_D) nanosheets with expanded tunnel structure, exceptional conductivity andsuperior structural stability for aqueous ZIBs, showing fast Zn²⁺diffusion and excellent performance. The resulted ZIBsafforda remarkably high capacityof408 mAh g^-1at 0.1 A g^-1, ultrahigh stability of 94.1% retention over 4000 cycles at 1.0 A g^-1, and exceptional energy density of287 Wh kg^-1, which are superior to many reported ZIBs. Furthermore, it is revealed that from theoretical and experimental studies the oxygen defects intrinsically contribute to the narrow bandgap and high electrical conductivity of NVO_Dto greatly boost the performance. The reversible storage of Zn²⁺in NVO_Dis further illustrated via different in-situ characterization techniques. Moreover,the flexible soft-packaged batteries alsodemonstratesuperior capacity retention of 91 % after 200 cycles.Therefore, the exploration inNVO_Dmaterials with rich oxygen defects will supplyan attractive approach for designing high-performance andflexible ZIBs.