Hierarchical carbon nanofiber/NiCo2O4 composites as electrode for high-performance supercapacitors

Carbon Nanofibers (CNFs)/transition metal oxides (TMOs) composites have obtained much attention as supercapacitor electrode with benefits from the superior electrical conductivity of carbon materials and high capacity of TMOs. However, nano-size TMOs is prone to agglomeration and hard to grow efficiently and uniformly on CNFs due to the surface of CNFs lack effective targets, which limits its performance. In this paper, different hierarchical structures of CNFs-NiCo ₂ O ₄ were prepared and assembled as supercapacitor electrode. The results showed that CNFs-NiCo ₂ O ₄ prepared by treatment of potassium permanganate exhibited a high capacitance of 1175 F g ^− 1 at a current density of 1 A g ^− 1 and long-term cycling stability, with 93% capacitance retention after 3000 cycles. The excellent electrochemical performance could be attributed to that more active sites were introduced on the CNFs after solvent treatment, which were beneficial for NiCo ₂ O ₄ to grow uniformly on CNFs. This approach provides a new strategy for controllable design and synthesis of homogeneous hierarchical CNFs/TMOs composites.