The development of aqueous ammonium ion batteries is currently in its infancy. Searching for suitable electrode materials is one of the most important jobs in preparing high-performance batteries. In this work, we report a one-step hydrothermal method to successfully synthesize novel K-V-Fe Prussian blue analogues nanocubes (PBAs NCs) by using oxalic acid as the reducing agent. The obtained electrode materials effectively combine the high electrochemical activity of vanadium-contained ions with the excellent structural stability of Prussian blue frame, thus ensuring their high capacity for electrochemical energy storage and excellent cycling stability. The optimal K-V-Fe PBAs NCs can achieve a high specific capacity of 92.85 mAh·g⁻¹ at a current density of 2 A·g⁻¹, outstanding cycling stability with a capacity retention of 91.44% (84.9 mAh·g⁻¹) after 2000 cycles at 2 A·g⁻¹ and good rate capability with a specific capacity of 46.2 mAh·g⁻¹ at 5 A·g⁻¹. This strategy of combine vanadium element with open three-dimensional framework provides a new way for selecting and improving electrode materials suitable for electrochemical energy storage. And the present K-V-Fe PBAs NCs will be a promising candidate for aqueous rechargeable ammonium-ion batteries due to their high capacity, reasonable cost and excellent cycling stability.

水性铵离子电池的开发目前处于起步阶段。在制备高性能电池中，寻找合适的电极材料是最重要的工作之一。在这项工作中，我们报告了一步水热法，以草酸为还原剂成功地合成了新型KV-Fe普鲁士蓝类似物纳米立方体（PBAs NCs）。所获得的电极材料有效地将含钒离子的高电化学活性与普鲁士蓝框的优异结构稳定性相结合，从而确保了其高的电化学能量存储能力和优异的循环稳定性。最佳KV-Fe PBA NCs在2 A·g ^-1的电流密度下可实现92.85 mAh·g ^-1的高比容量，具有91.44％的容量保持优秀的循环稳定性（84.9毫安·克^-1）在2所述的2000次循环之后·克^-1和良好的倍率性能与46.2毫安的比容量·克^-1在5 A·克^{- 1}。钒元素与开放式三维框架相结合的这种策略为选择和改进适合电化学能量存储的电极材料提供了一种新途径。目前的KV-Fe PBA NCs由于其高容量，合理的成本和出色的循环稳定性，将成为水性铵离子电池的有前途的候选者。