Preparation Of Biomass Carbon And Its Supercapacitive Properties

Waste biomass has received considerable attentions all over the world due to its low cost, thewide raw material sources and reproducibility. Using biomass as raw material of carbon productioncan reduce the cost and ease the problem of environment caused by the direct burning of wastebiomass. In this thesis, biomass carbons and their supercapacitive properties were studies. The mainpoints were as follows：Biomass carbons were prepared by impregation-activation via one-step method, wherein rapeseed shell、plane tree bark、peach pit、longan rind and durian rind were used as carbon precursor, KOHwas used as active agent. The SEM images showed the samples had macroporous structures and N2adsorption-desorption analysis showed the samples have nano-scaled channels or pores, which weremore advantageous for the transmission of electrolyte. The results of electrochemical tests indicatedthat the specific capacitance value of the sample was about225F/g at the current density of1A/g.Biomass carbons were prepared by impregation-activation via two-step method, wherein planetree bark、peach pit、longan rind and durian rind were used as carbon precursor, KOH was used asactive agent. In addition, biomass carbons with high specific surface area were prepared by usingwaste plane tree bark via carbonization-activation route. It was found that the mass ratio between theactive agent and the plane tree bark played a significant role in the development of the specific surfacearea and specific capacitance of the samples. When the mass ratio between the active agent and theplane tree bark was3:1, the sample possessed the largest specific surface area of2141m2/g and thespecific capacitance value of334F/g at the current density of1A/g.Biomass carbons with high specific surface area were prepared by using rape seed shell viahydrothermal method. Compared with biomass carbons prepared via impregation-activation, thesamples had higher ratio discharge property. The hydrothermal method provided a new method for thepreparation of biomass carbons with macroporous structures and large specific surface areas.Biomass carbons with high specific surface area and secondary pore structure were prepared byusing rape seed shell via vacuum freezing method. Compared with the common biomass carbon of thesingle pore channel, the specific capacitance of the sample was about177F/g at the current density of20A/g, indicating the sample had excellent supercapacitive behaviors.