A superhigh-temperature hydrothermal treatment to construct CoFe2O4@C/graphene composite for enhanced lithium storage

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.