GeP is a promising anode material for sodium ion battery due to better conductivity, relatively high theoretical capacity and improved mechanical endurance compared to phosphorus and other phosphides. However unsatisfied rate capability and cycling stability is still an annoying issue that hinders the application of GeP. Here, GeP was hybridized with P doped carbon (PPC) derived from low-cost coal tar pitch to prepare composite electrode. Through ball-milling process, the GeP and PPC was homogenously mixed and form fused, secondary particles as confirmed by electron microscope. The formation of P-C and P-O-C bond between GeP and carbon matrix was evidenced by XPS, and prompted by P doping level and O content in PPC. The electrochemical performance of the composite electrodes was evaluated, demonstrated much enhanced properties compared to bare GeP and also GeP/carbon black electrode. High reversible capacity of 781 mAh/g was achieved by GeP/PPC-950 at 0.05 A/g. At higher current density of 2 A/g, the capacity can maintain at 360 mAh/g, 46% of the value that obtained at 0.05 A/g. The correlation between the structure of carbon and battery performance was discussed. The improvement in battery performance can be attributed to suppressed volume expansion and good conductive network of the GeP/PPC composite, which affected by P doping level and O content of PPC.

中文翻译：

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通过球磨制备沥青衍生的 P 掺杂碳/GeP3 复合材料，以增强钠离子存储

与磷和其他磷化物相比，GeP 具有更好的导电性、相对较高的理论容量和更高的机械耐久性，是一种很有前景的钠离子电池负极材料。然而，倍率性能和循环稳定性不令人满意仍然是阻碍GeP应用的一个恼人的问题。在这里，GeP 与源自低成本煤焦油沥青的磷掺杂碳（PPC）杂化以制备复合电极。通过球磨过程，GeP 和 PPC 均匀混合并形成熔融的二次颗粒，经电子显微镜证实。 XPS证明了GeP和碳基体之间PC和POC键的形成，并由PPC中的P掺杂水平和O含量促进。对复合电极的电化学性能进行了评估，结果表明与裸 GeP 和 GeP/炭黑电极相比，性能大大增强。 GeP/PPC-950 在 0.05 A/g 电流下实现了 781 mAh/g 的高可逆容量。在2 A/g的较高电流密度下，容量可以保持在360 mAh/g，是0.05 A/g时的46%。讨论了碳的结构与电池性能之间的相关性。电池性能的改善可归因于GeP/PPC复合材料抑制的体积膨胀和良好的导电网络，这受到PPC的P掺杂水平和O含量的影响。