ABSTRACT Cobalt ferrite (CoFe2O4) has drawn great attraction due to its high theoretical specific capacity (916 mAh g−1), low cost, highlighted chemical stability and environmental benignity. However, it demonstrates poor electrochemical performance due to low instinctive electrical conductivity, huge volume expansion and serious collapse during repeated cycling. In this work, CoFe2O4@C/graphene composite is prepared through a superhigh-temperature hydrothermal treatment. Since the carbonisation process and formation of CoFe2O4 nanoparticles are simultaneously carried out in high pressure environment, which assures CoFe2O4 @C uniformly assembled on the graphene nanosheets without re-stacking. This composite delivers excellent electrochemical performance. A reversible capacity of 557.9 mAh g−1 remained after 500 cycles at 1 A g−1, and 395.2 mAh g−1 maintained after 1000 cycles at 5 A g−1, which is better than those of the most reports. This work provides a significantly simple and effective method to enhance the lithium storage of transition metal oxides.

中文翻译：

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超高温水热处理构建CoFe2O4@C/石墨烯复合材料以增强锂存储

摘要钴铁氧体（CoFe2O4）由于其理论比容量高（916 mAh g-1）、低成本、突出的化学稳定性和环境友好性而备受关注。然而，由于本征导电率低、体积膨胀大和重复循环过程中严重塌陷，它表现出较差的电化学性能。在这项工作中，通过超高温水热处理制备了 CoFe2O4@C/石墨烯复合材料。由于碳化过程和 CoFe2O4 纳米颗粒的形成是在高压环境中同时进行的，这确保了 CoFe2O4@C 均匀组装在石墨烯纳米片上而无需重新堆叠。这种复合材料具有出色的电化学性能。在 1 A g-1 和 395 下循环 500 次后，可逆容量仍为 557.9 mAh g-1。在 5 A g-1 下循环 1000 次后仍保持 2 mAh g-1，优于大多数报道。这项工作提供了一种非常简单有效的方法来增强过渡金属氧化物的锂存储。