Ca doping NH ₄ V ₄ O ₁₀ with enhanced zinc‐ion storage ability and structural stability for high‐performance aqueous zinc‐ion batteries

Abstract NH 4 V 4 O 10 (NVO) as a cathode material of zinc‐ion battery is prone to collapse in the repeated process of embedding and de‐embedding of Zn 2+ , and its application is limited by the instability of the material. Here, calcium‐doped ammonium vanadate (CNVO) is successfully synthesized via a one‐step hydrothermal approach. The intercalated Ca 2+ in NVO serves as a firm pillar between the [VO n ] layers to maintain the structure stability during the ion insertion/extraction process. Furthermore, density functional theory (DFT) calculations and ex situ experiments reveal that CNVO demonstrates higher affinity and conductivity compared to NVO, which can effectively improve the kinetics of Zn 2+ diffusion, reduce the electrostatic repulsion of Zn 2+ during intercalation and deintercalation, and maintaining the stability of the layered structure. As a result, the CNVO material demonstrates outstanding electrochemical performance, delivering a specific capacity of 183 mAh·g −1 at 5 A·g −1 . Moreover, it sustains an impressive 91% capacity retention after 1300 cycles.