Red phosphorus (RP) is a promising anode material for potassium-ion batteries because of its theoretical capacity of 865 mAh g^-1 delivered at an average potential of 0.5 V vs K⁺/K. However, its alloy reaction to form KP entails a volume expansion of 162% resulting in severe stresses that lead to SEI and electrode fracture, loss of electric contact, and ultimately reduced cycle life. Moreover, its low electronic conductivity (10^-14 S cm^-1) limits rate capability. Here, we report a RP-graphite composite prepared by a two step ball milling procedure to control particle size and optimize carbon coating. Raman operando on graphite in the composite suggests that the carbon coating reversibly expands and contracts due to the volume expansion of RP particles. Electrodes prepared with the composites achieve high capacity (723 mAh g^-1_P) at C/20 and retaining 75% at 5C. It also shows very good cycling stability, retaining more than 96% of the capacity after 100 cycles at 1C.

红磷 (RP) 是一种很有前途的钾离子电池负极材料，因为它在 0.5 V vs K ⁺ /K的平均电位下提供865 mAh g ^{-1 的}理论容量。然而，其形成 KP 的合金反应需要 162% 的体积膨胀，从而导致严重的应力，从而导致 SEI 和电极断裂、电接触损失，并最终降低循环寿命。此外，它的低电子电导率（10 ^-14 S cm ^-1) 限制速率能力。在这里，我们报告了通过两步球磨程序制备的 RP-石墨复合材料，以控制粒径和优化碳涂层。复合材料中石墨的拉曼操作表明，由于 RP 颗粒的体积膨胀，碳涂层可逆地膨胀和收缩。用复合材料制备的电极在 C/20 下实现了高容量（723 mAh g ^-1 _P），并在 5C 下保持了 75%。它还显示出非常好的循环稳定性，在 1C 下循环 100 次后仍保持超过 96% 的容量。