Potassium manganese hexacyanoferrate (KMnHCF) can be used as a positive electrode for potassium‐ion batteries because of its high energy density. The effect of particle size and [Fe(CN)₆]ⁿ⁻ vacancies on the electrochemical potassium insertion of KMnHCFs was examined through experimental data and theoretical calculations. When nearly stoichiometric KMnHCF was synthesized and tested, smaller particle sizes were found to be important for achieving superior electrochemical performance in terms of capacity and rate capability. However, even in the case of larger particles, introducing a suitable number of anion vacancies enabled KMnHCF to exhibit comparable electrode performance. Electrochemical tests and density functional theory calculations indicated that anion vacancies contribute to the enhancement of K⁺ ion diffusion, which realizes good electrochemical performance. Structural design, including crystal vacancies and particle size, is the key to their high performance as a positive electrode.

中文翻译：

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粒径和阴离子空位对六价高锰酸铁锰钾中电化学钾离子注入的影响

六氰合铁酸锰锰钾（KMnHCF）具有高能量密度，因此可以用作钾离子电池的正极。颗粒大小和的[Fe（CN）的效果₆ ] ^{ñ -}通过实验数据和理论计算，研究了KMnHCFs的电化学钾插入空位。当合成和测试接近化学计量的KMnHCF时，发现较小的粒径对于在容量和速率能力方面实现卓越的电化学性能很重要。但是，即使在较大颗粒的情况下，引入合适数量的阴离子空位也可使KMnHCF表现出可比的电极性能。电化学测试和密度泛函理论计算表明，阴离子空位有助于增加K ⁺离子的扩散，实现了良好的电化学性能。结构设计（包括晶体空位和粒径）是其作为正极的高性能的关键。