Low-cost Prussian blue analogs (PBAs) have attracted great attentions as a group of promising cathodes for sodium-ion batteries (SIBs) due to their tailorable and open frameworks which endue the possibility of ultrahigh Na⁺ diffusion kinetics. Herein, a unique discharging plateau elevation was firstly determined in the iron hexacyanoferrate. The synergy between the crystal field and ligand field stabilization energy in the OH-coordinated Fe sites lowers the activation energy barrier of low-spin Fe, thus inducing the intercalation pseudocapacitance. Furthermore, we prove that the Na⁺ storage mechanism of high-spin Fe redox reaction features an ion–diffusion behavior while the low-spin Fe redox reaction shows a pseudocapacitance behavior. Benefitting from the improved ionic diffusivity in intercalation pseudocapacitance, the full cell achieves an outstanding rate performance and long-term cycling stability of over 3000 cycles at 500 mA g⁻¹. It is expected that manipulating Fe redox kinetics of the PBAs through inducing special coordinated groups could be a new pathway towards the design of practical high-voltage SIBs.

低成本的普鲁士蓝类似物 (PBA) 作为一组有前途的钠离子电池 (SIB) 阴极，由于其可定制和开放的框架而引起了极大的关注，这些框架赋予了超高 Na ⁺扩散动力学的可能性。在此，首次在六氰基高铁酸铁中确定了独特的放电平台高程。OH-配位Fe位点中晶场和配体场稳定能之间的协同作用降低了低自旋Fe的活化能垒，从而诱导了插层赝电容。此外，我们证明 Na ⁺高自旋 Fe 氧化还原反应的存储机制具有离子扩散行为，而低自旋 Fe 氧化还原反应显示赝电容行为。受益于嵌入赝电容中改进的离子扩散率，全电池实现了出色的倍率性能和在 500 mA g ^-1下超过 3000 次循环的长期循环稳定性。预计通过诱导特殊的配位基团来操纵 PBAs 的 Fe 氧化还原动力学可能是设计实用高压 SIBs 的新途径。