Preparation Of Biomass-based Activated Carbon And For Electrochemical Supercapacitors

A large number of the properties of biomass materials-such as renewable, low-cost, earth-abundant, specific structures, mechanical property and many others-are very attractive. These properties endow that biomass could replace some key materials in electrochemical energy storage systems. The main contents are as follows:Activated carbon with an ultrahigh specific surface area(3160 m2 g-1) and large pore volume(1.73 cm3 g-1) was prepared using agaric as the raw material and KOH as the activating reagent. The morphology and structure of the as-prepared sample were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption-desorption measurement. The results indicated that the materials acquire the largest specific surface area and pore volume when the mass ratio between the KOH and the agaric was 4:1. The as-prepared carbon achieved high specific capacitance of 292 F g-1 at a current density of 1A g-1 in 6 M KOH electrolyte.Biomass carbon with hierarchical pore structure was prepared using hydrothermal carbonization, pleurotus ostreatus as carbon precursor and KOH as the activating agent. The results indicated that the sample possessed a large surface area of 1553 m2 g-1 and a specific capacitance of about 203 F g-1 at a current density of 1 A g-1. The sample get a high specific capacitance of 169 F g-1 when the the current dnsity increase to 10 A g-1, indicating excellent electrochemical performance.Nitrogen-doped activated carbon material with high specific surface area was prepared using cotton as the raw material, urea as the doping agent, and KOH as the activating reagent.The results demonstrated that a cotton-derived activated carbon material with high specific surface area(2714 m2/g) and nitrogen content(6.31%) was achieved. The specific capacitance of the nitrogen-doped activated carbon was 231F/g in 1 M H2SO4 at the scan rate of 10 m V/s, indicating excellent electrochemical performance.Highly mesoporous carbons with large pore size distribution have been prepared by self-activation of mango shells at temperatures 1000??The BET specific surface area reached 1305 m2 g-1. The sample get a specific capacitance of 130 F g-1 at the scan rate of 5 m Vs-1. Capacity retention of samples remain 82% when the scan rate increase to 100 m Vs-1,indicating a high rate performance.