Copper Pyrovanadate Nanoparticles with Favorable Interplanar Spacing Enable Enhanced Ammonium Storage Performance

Aqueous ammonium-ion batteries (AAIBs) have gained significant prominence in the field of aqueous energy storage primarily due to their exceptional safety, low cost, and outstanding electrochemical performance. Despite their promise, AAIBs currently remain in the early stages of development, making the exploration and design of advanced electrode materials critical for enhancing their performance. In this research, a simple one-step hydrothermal approach was used to prepare Cu 3 (OH) 2 V 2 O 7 ·2H 2 O material (CuVO), with its application in AAIBs being reported and systematically investigated for the first time. The synthesized CuVO exhibits a uniform and fine nanosphere structure with a large interlayer spacing. This unique structure not only ensures a sufficient contact area with the electrolyte but also provides an abundance of active sites for electrochemical reactions, endowing it with excellent performance characteristics. Electrochemical tests reveal that CuVO delivers a specific capacity of CuVO of 279 mAh g –1 at 0.1 A g –1 . Notably, after 1000 cycles at 1 A·g –1, the specific capacity remains at 87.8 mAh·g –1, with a high-capacity retention rate of 86.7%. Electrochemical kinetic analysis demonstrates that diffusion behavior is dominated by the electrochemical reaction of the material and the material has a highly stable structure. In conclusion, CuVO’s high specific capacity and excellent cycle stability establish it as a viable candidate for the development of high-performance electrode materials in aqueous ammonium-ion batteries, offering valuable insights for advancing AAIB technology.