Na-rich Na_xFeFe(CN)₆ (NFF) in terms of low cost and high theoretical capacity has been considered to be a potential cathode material for aqueous sodium ion batteries (SIBs). However, low sodium content, poor Columbic efficiency (CE) and rapid capacity degradation impede their practical application. Herein, the effect of low-level Ni doping in NFF as cathode materials in 1 M NaNO₃ electrolyte has been investigated, which were synthesized via a citrate-assisted co-precipitation route. NFF substituted with 23% Ni²⁺ exhibited the best electrochemical behaviors, which delivers a discharge capacity of 105.9 mAh g⁻¹ at 200 mA g⁻¹ and 73.1% capacity retention over 1000 cycles with an average CE of 99.8% at 1000 mA g⁻¹. A reversible capacity of 55.5 mAh g⁻¹ can be obtained even at a high current density of 2000 mA g⁻¹. The Ni substitution strategy was evidenced to be a scalable method to prepare promising cathode materials with excellent cycling stability for high-performance aqueous SIBs.

就低成本和高理论容量而言，富含Na的Na _x FeFe（CN）₆（NFF）被认为是水性钠离子电池（SIB）的潜在阴极材料。但是，钠含量低，哥伦布效率（CE）差和容量快速下降阻碍了它们的实际应用。在本文中，已经研究了通过柠檬酸盐辅助共沉淀途径合成的，在1M NaNO ₃电解质中作为阴极材料的NFF中低浓度Ni掺杂的效果。NFF取代有23％的Ni ²⁺表现出最佳的电化学行为，它提供的105.9毫安g的放电容量^-1在200mA克^-1和在1000个循环中保持73.1％的容量，在1000 mA g ^-1时的平均CE为99.8％。即使在2000 mA g ^-1的高电流密度下，也可得到55.5 mAh g ^-1的可逆容量。事实证明，镍替代策略是一种可扩展的方法，用于制备有希望的阴极材料，该材料具有出色的循环稳定性，可用于高性能水性SIB。