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

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.

KEYWORDS:

• CoFe₂O₄
• superhigh-temperature hydrothermal treatment
• graphene
• carbon coating

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research is financially supported by the Natural Science Foundation of Shaanxi Province of China [2016JM2024]; International Science and Technology Cooperation Program of Shaanxi Province [2020KW-024] and China Postdoctoral Science Foundation [2016M590908].