Study On Electrode Materials For Supercapacitor Based On Carbon Nanotubes

Supercapacitors have been recognized as unique energy storge devices that fill the gap between conventional dielectric capacitors and rechargeable batteries. Since supercapacitors have the advantages of high power density, high energy density and long cycle life, they have been used widely in the fields such as mobile telecommunication, information technology, consumer electronics, aviation and aerospace and so on, and have been attraction more and more attention throughout the world. Nowadays, studies on supercapacitors are mainly focused on the preparation of high performance electrode material. A new CNTs skeleton network porous carbon material with improving electric conductivity and high mesopores ratio has been prepared by using a polymer blend and copolymer carbonization method. The effect of preparation condition on pore structure and capacitance performance is studied.Firstly, Phenol-formaldehyde resin (PF) is used as carbon precursor polymer and gelatin as pore former polymer, porous carbon for supercapacitors has prepared successfully by polymer blend carbonization method. The effect of PF/gelatin mass ratio on pore structure and capacitance performance is studied. Based on the above experiment, the purified CNTs is dispersed into gelatin, CNTs skeleton network porous carbon material has been prepared successfully. The result of electrochemical test indicates: When the composition of PF/gelatin was kept at 1:1, the content of CNTs of 20%, the temperature of carbonization at 800℃, the carbonization time of 1h, the specific capacitance of CNTs skeleton network porous carbon reached 168 F/g, a low equivalent series resistance of 0.8Ωcm~2 is obtained.Secondly, melamine-formaldehyde resin (MF) is used as carbon precursor polymer, gelatin is used to coat CNTs, carbon nanotube-implanted mesoporous carbon spheres (CNTs-MCS) has been prepared successfully.by using gelatin as a soft template via a polymerization-induced colloid aggregation (PICA) method. The result of electrochemical test indicates: Using the CNTs-MCS as the electrode material for supercapacitor without a conductivity additive, a low equivalent series resistance of 0.9Ωcm~2 and a maximum specific capacitance of 189 F/g with a measured power density of 8 kW/kg at energy density of 26.3 Wh/kg are obtained. Cyclic voltammetry (CV) curves of CNTs-MCS show good symmetries, and charge-discharge performance is remarkable.