Preparation of NaV6O15 Nanosheet Cathodes with High Cycling Performance and Good Capacity Retention Rate in Aqueous Zinc‐Ion Batteries

Aqueous zinc‐ion batteries (AZIBs) have become a promising alternative energy storage device due to their lower cost and better safety performance than lithium‐ion batteries (LIBs). However, the biggest challenge is the need to develop electrode materials with higher capacity and longer life than LIBs at present. Herein this work, a tunnel‐structured sodium vanadate (NaV 6 O 15 ) is synthesized by molten salt method as the cathode materials for AZIBs. The prepared NaV 6 O 15 nanosheets have a high specific capacity of 325 mAh g −1 at a current density of 0.1 A g −1 , and the capacity retention rate is as high as 127.08% under 1000 cycling at a current density of 1 A g −1 . This excellent performance is mainly attributed to the stable tunneled structure, which provides an effective diffusion path for Zn 2+ insertion and avoids structural damage. Herein the subsequent cycles, Zn 2+ is mainly inserted/extracted in NaV 6 O 15 and Zn 3 (OH) 2 V 2 O 7 ·2H 2 O. The preparation of NaV 6 O 15 cathode materials and the molten salt method provide a certain reference value for the development of AZIBs in this work.