Abstract Co0.9Cu0.1Si hydrogen storage alloy is fabricated by mechanical alloying method. The cobalt/graphene composite (Co/rGO) is obtained via a facile one-pot reduction process. The Co/rGO materials exhibit unique reticular globular morphology. After ball milling, Co/rGO particles are covered on the Co0.9Cu0.1Si alloy surface. For comparison, Co0.9Cu0.1Si coated with reduced graphene oxide (rGO) is also fabricated. The Co0.9Cu0.1Si + Co/rGO composite exhibits higher discharge capacity than rGO coated alloy (541.6 mAh/g) and matrix Co0.9Cu0.1Si (516.8 mAh/g). A Cmax of 582.9 mAh/g is achieved for Co0.9Cu0.1Si + Co/rGO. Electrochemical measurements also show that the high-rate dischargeability and cycle stability are improved. The graphene can provide high conductivity and Co particles in the Co/rGO may participate in the reversible redox reactions. The special structure of Co/rGO may enhance the electrocatalytic activity of the Co0.9Cu0.1Si surface. A synergistic effect between graphene and cobalt species in the Co/rGO composite may be favorable for expediting the charge transfer and facilitating the hydrogen diffusion, thus improving the electrochemical and kinetic properties of Co0.9Cu0.1Si alloy.

中文翻译：

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Co/rGO复合材料包覆改善Co0.9Cu0.1Si储氢合金电化学性能

摘要 采用机械合金化方法制备Co0.9Cu0.1Si储氢合金。钴/石墨烯复合材料（Co/rGO）是通过简单的一锅法还原工艺获得的。Co/rGO 材料表现出独特的网状球状形态。球磨后，Co/rGO 颗粒覆盖在 Co0.9Cu0.1Si 合金表面。为了进行比较，还制造了涂有还原氧化石墨烯 (rGO) 的 Co0.9Cu0.1Si。Co0.9Cu0.1Si + Co/rGO 复合材料表现出比 rGO 涂层合金（541.6 mAh/g）和基体 Co0.9Cu0.1Si（516.8 mAh/g）更高的放电容量。Co0.9Cu0.1Si + Co/rGO 的 Cmax 为 582.9 mAh/g。电化学测量还表明，高倍率放电能力和循环稳定性得到改善。石墨烯可以提供高导电性，Co/rGO 中的 Co 颗粒可以参与可逆的氧化还原反应。Co/rGO 的特殊结构可以增强 Co0.9Cu0.1Si 表面的电催化活性。Co/rGO 复合材料中石墨烯和钴物种之间的协同效应可能有利于加速电荷转移和促进氢扩散，从而改善 Co0.9Cu0.1Si 合金的电化学和动力学性能。