Preparation and performance of sodium vanadate cathode with microporous structure for aqueous zinc - Ion batteries

Aqueous zinc - ion batteries (AZIBs) stand out among numerous battery systems due to their remarkable features such as high discharge capacity, low cost, and environmental friendliness . They are regarded as one of the promising alternatives for advanced energy storage systems . However, traditional AZIBs cathode materials still face many problems, including structural collapse and the dissolution of active substances. In this study, a precursor containing ammonium ions was prepared by the hydrothermal method . Through calcination in air, part of the ammonium ions escaped from the main structure in the form of ammonia gas, thus obtaining a sodium vanadate (NaV 6 O 15 ) cathode material rich in a microporous structure. With the introduction of micropores , the overall electrochemical performance of the material has been significantly improved. The first charge/discharge specific capacity of the electrode reaches 500.2/497.5 mAh g −1 . After 70 cycles, the specific capacity is 450.7 mAh g −1 , and the capacity retention is approaching 100 %. Based on the modified electrode , the specific capacity has increased by 158.1 mAh g −1 . The results of ex-situ XPS spectra indicate that the structure of the NaV 6 O 15 cathode material is relatively stable and suitable for the insertion and extraction of Zn 2+ .