In-situ Preparation Of Graphitized Porous Carbon/Nickel Composite Materials For Electrochemical Performance

With the rapid development of high technology field, conventional activated carbon has been unable to meet the demands for high energy density and high power density of electronic devices. The research and development of new carbon-based materials have become a trend. Graphitized carbon/metal composites have shown great application prospect in the process of energy storage and conversion owing to their excellent features. In this thesis, a spherical precursor with well-developed pore structure was prepared by using alkali lignin as a carbon source. Then, lignin activated carbon(LAC) with multi-stage pore structure was prepared by carbonization and activation of the precursor. Finally, in LAC supported nickel acetate(Ni Ac) system, we produced carbon/nickel(C/Ni) composites by in-situ nickel catalytic graphitization of carbon. The graphite process of nickel catalyzed carbon and its effect on the electrochemical properties were studied. The main results were as follows:(1) The amount of catalyst, heat treatment temperature and time were investigated in order to study the influence of reaction conditions on the degree of graphitization. Research showed that the optimal reaction condition was LAC/Ni Ac mass ratio of 1: 1.5, the heat treatment temperature of 1000 oC, and heat treatment time of 1.5 h, in which the degree of graphitization was the best. R(ID/IG) was 0.831. The resistivity was 0.174 Ω/cm.(2) The effects of various factors on the electrochemical properties of graphitized C/Ni composites were studied systematically. When the LAC/Ni Ac mass ratio was 1: 1.5, heat treatment temperature was 850 oC, and the heat treatment time was1.5 h, the capacitance value of C/Ni composites reached to 261.4 F/g. The capacitance value was increased by nearly three times under the same conditions without catalyst, which enhanced the storage and conductivity of the material in the electrolyte.(3) Based on the analysis of the structure characteristics of C/Ni composites, the reaction mechanism was discussed about in-situ carbon reduced nickel and nickel catalytic graphitization of carbon. We have established a method for the preparation of C/Ni composites by in-situ nickel catalytic graphitization of carbon. The C/Ni composite functional materials were prepared with the specific surface area of 3058 m2 g-1 and the average pore size of 2.36 nm.