Abstract A novel NASICON-type K0.24Na2.76Fe2(PO4)3 (K0.24NFP) is synthesized via a simple solid-state reaction method. K-doped method can enlarge lattice distance and restrain the structure dilapidation from Na3Fe2(PO4)3 to Na5Fe2(PO4)3. Comparison with undoped-Na3Fe2(PO4)3 (NFP) sample (82.1 mAh g−1), K0.24NFP electrode shows a 101.3 mAh g−1 discharge capacity at 10 mA g−1, which up to 97% of theoretical capacity. As for rate capability performance, a high reversible capacity of 73.6 mAh g−1 at 1000 mA g−1. The cycle stability performance measurement results indicate that the discharge capacity of K0.24NFP electrode is up to 93.7 mAh g−1 after 500 cycles at 100 mA g−1. The excellent electrochemical performance is attributed to the improvement of structural stability and the highest intercalation-deintercalation kinetic of sodium-ions (DNa+ = 3.98 × 10−11) due to K-doped. Hence, the K-doped iron-based phosphate (K0.24Na2.76Fe2(PO4)3) should be a potential cathode material in sodium-ions batteries for scale energy storage.

中文翻译：

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用于钠离子储能电池的高稳定性结构K掺杂Na3Fe2(PO4)3正极材料

摘要 通过简单的固相反应方法合成了一种新型NASICON 型K0.24Na2.76Fe2(PO4)3 (K0.24NFP)。K掺杂法可以扩大晶格间距，抑制Na3Fe2(PO4)3到Na5Fe2(PO4)3的结构破坏。与未掺杂的 Na3Fe2(PO4)3 (NFP) 样品 (82.1 mAh g-1) 相比，K0.24NFP 电极在 10 mA g-1 下的放电容量为 101.3 mAh g-1，高达理论容量的 97%。至于倍率性能，在 1000 mA g-1 时具有 73.6 mAh g-1 的高可逆容量。循环稳定性性能测量结果表明，K0.24NFP电极在100 mA g-1下循环500次后放电容量高达93.7 mAh g-1。优异的电化学性能归因于结构稳定性的提高和钠离子的最高嵌入-脱嵌动力学（DNa+ = 3. 98 × 10−11) 由于 K 掺杂。因此，掺钾铁基磷酸盐（K0.24Na2.76Fe2(PO4)3）应该是钠离子电池规模储能的潜在正极材料。