Prussian blue and its analogues (PBAs) have been recognized as one of the most promising cathode materials for room‐temperature sodium‐ion batteries (SIBs). Herein, we report high crystalline and Na‐rich Prussian white Na₂CoFe(CN)₆ nanocubes synthesized by an optimized and facile co‐precipitation method. The influence of crystallinity and sodium content on the electrochemical properties was systematically investigated. The optimized Na₂CoFe(CN)₆ nanocubes exhibited an initial capacity of 151 mA h g⁻¹, which is close to its theoretical capacity (170 mA h g⁻¹). Meanwhile, the Na₂CoFe(CN)₆ cathode demonstrated an outstanding long‐term cycle performance, retaining 78 % of its initial capacity after 500 cycles. Furthermore, the Na₂CoFe(CN)₆ Prussian white nanocubes also achieved a superior rate capability (115 mA h g⁻¹ at 400 mA g⁻¹, 92 mA h g⁻¹ at 800 mA g⁻¹). The enhanced performances could be attributed to the robust crystal structure and rapid transport of Na ions through large channels in the open‐framework. Most noteworthy, the as‐prepared Na₂CoFe(CN)₆ nanocubes are not only low‐cost in raw materials but also contain a rich sodium content (1.87 Na ions per lattice unit cell), which will be favorable for full cell fabrication and large‐scale electric storage applications.

中文翻译：

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高结晶度普鲁士白色纳米立方体作为钠离子电池的有希望的阴极

普鲁士蓝及其类似物（PBA）被公认为是室温钠离子电池（SIB）最有希望的正极材料之一。在此，我们报告了通过优化且简便的共沉淀方法合成的高结晶度和富钠普鲁士白Na ₂ CoFe（CN）₆纳米立方体。系统地研究了结晶度和钠含量对电化学性能的影响。优化的Na ₂ CoFe（CN）₆纳米立方体的初始容量为151 mA h g ^-1，接近其理论容量（170 mA h g ^-1）。同时，Na ₂ CoFe（CN）₆阴极表现出出色的长期循环性能，在500次循环后仍保持其初始容量的78％。此外，钠₂的CoFe（CN）_6个普鲁士白色纳米立方体还实现了优异的倍率性能（115毫安ħ克^-1以400mA克^-1，92毫安ħ克^-1以800mA克^-1）。性能的提高可归因于坚固的晶体结构和Na离子通过开放框架中大通道的快速运输。最值得注意的是，所制备的Na ₂ CoFe（CN）₆ 纳米立方体不仅原料价格低廉，而且钠含量高（每个晶格单位单元含1.87 Na离子），这对于全电池制造和大规模电存储应用将是有利的。