Facile Synthesis of Carbon Supported Porous Metal Oxide Nanofibers for Prospective Supercapacitor Electrodes

Abstract

Supercapacitors (SCs) have received great attention due to their rapid charging-discharging rate and long life cyclic stability. Transition metal oxides (TMOs) have been widely investigated as electrode materials for their theoretically higher specific capacitance. Here, a facile and effective synthesis route of metal oxide embedded in porous carbon nanofiber support has been developed. First, the corresponding metal salts were dissolved in a homogenous polyacrylonitrile (PAN) and cellulose diacetate (CDA) polymer solution. Fresh fibers were obtained by electrospinning the polymer solution. Then it was annealed at high temperature in N 2 atmosphere to obtain the carbonized samples. During the thermal treating process, metal salts are converted to less oxidation states or even only metal, while PAN forms carbon backbone and CDA as the sacrificial polymer is burned to form pores. For samples with only metal formed, the hydrothermal treatment is subsequently performed for further oxidation. When tested for supercapacitors, the 3D connected porous nanofiber structure can provide transport channel for electrolyte during charging-discharging process. In detail, porous TMOs/carbon fibers including cheap and high performance TMOs, such as NiO, Co 3 O 4 , MnO 2 and ZnO based materials, or even multiple metal TMOs will be systematically investigated. The effects of different annealing temperature on the compositions, porous structure and electrochemical performance will also be investigated. The preliminary results show that TMOs supported by the porous carbon fiber demonstrated greatly improved electrochemical performance, indicating that this facile synthesis method can be a promising alternative to prepare TMOs electrode materials with high performance.