Preparation Of Biomass - Derived Porous Carbon And Its Complexes And Its Electrochemical Properties

Supercapacitors, also known as electrochemical capacitors, because of its specific capacitance, long cycle life, working principle is simple and high power density and been more and more attention. As for its porous structure and possessing a high specific surface area, awesome performance of electrochemical and low cost, has become the nearly most widely used electrode materials for supercapacitor. The transition metal oxide electrode material with its higher specific capacitance obtained researchers’attention. A wide range of biomass resources are widely distributed, and its rich reserves and low prices, is a extremely significant renewable resource, it can achieve the sustainable use and development cycle. Meanwhile, biomass is a renewable carbon carrier naturally occurring, convert it to make the best of new features carbon materials, there is a big space for development. Recently, the use of biomass for preparing porous carbon material is a hot research, the use of biomass as a raw material can not only save costs, but also mitigate environmental pollution problems caused by a large number of waste biomass burning caused. A variety types of biomass and low cost, which is the nature of the content of chitosan second category polysaccharide after cellulose, and lotus shell is ansignificant raw material resources, the vast majority of rice husk as litter or as low fuel, wasting huge energy. This selection of water-soluble chitosan and lotus shell of carbon materials were prepared porous carbon-based electrode materials, the specific content as followsas follows:(1) Direct hydrothermal carbonization rich in water-soluble chitosan mesoporous porous sheet material, and further product was obtained by high-temperature carbonization, finally, we get a kind of plate-like chitosan sample via a simple way. The results show:after 800℃ carbonized, porous carbon material produced specific capacitance of 166 F g-1 after 2000 cycles, the capacity holding rate of laps around 98%.(2) In-situ composites were prepared porous carbon/Fe3O4 composites and studied the content of transition metal composite materials for supercapacitors behavior. When the mass of the transition metal to carbon ratio of 4:5, the porous carbon/Fe3O4 composites at 0.05 A g-1 specific capacitance current density 299 F g-1, when the current density is increased to 2 A g-1, the specific capacitance reduced by twenty point seven percent by. Porous carbon/Fe3O44has excellent charge-discharge cycling stability, the specific capacitance keep 84% after 2000 cycles.(3) We used loter shells as raw material, and the KOH as activating agent, using twosteps including carbonization and activated progresses, finally, the carbon material generated by biomass. In addition, we found that the amount of KOH and the activation temperature has a great influence on the specific surface area of the sample than Ihe capacity. When the mass ratio of activator lotus shell is 4:1, the specific surface area of the sample reaches a maximum SSA(2961 m2g-1) and the capacity was up to 345 F g-1 at 0.5 A g-1 current density.In addition, we also studied the situation at different activation temperature, the amount of different activators on its electrochemical performance.