Electrospun Carbon Nanofibers with in Situ Encapsulated Co₃O₄ Nanoparticles as Electrodes for High-Performance Supercapacitors

A facile electrospinning method with subsequent heat treatments is employed to prepare carbon nanofibers (CNFs) containing uniformly dispersed Co₃O₄ nanoparticles as electrodes for supercapacitors. The Co₃O₄/CNF electrodes with ∼68 wt % active particles deliver a remarkable capacitance of 586 F g^-1 at a current density of 1 A g^-1. When the current density is increased to 50 A g^-1, ∼66% of the original capacitance is retained. The electrodes also present excellent cyclic stability of 74% capacity retention after 2000 cycles at 2 A g^-1. These superior electrochemical properties are attributed to the uniform dispersion of active particles in the CNF matrix, which functions as a conductive support. The onionlike graphitic layers formed around the Co₃O₄ nanoparticles not only improve the electrical conductivity of the electrode but also prevent the separation of the nanoparticles from the carbon matrix. (Graph Presented).