Preparation And Electrical Properties Of Heteroatom-doped Biomass-based Supercapacitor Electrode Materials

The porous carbon material is usually prepared from biomass and extensively used in the field of supercapacitors.In this study,residual bamboo and corncob were used as raw materials,which have the advantages of good surface modification,low cost,easy availability,and industrial application,and the heteroatom-doped supercapacitor electrode materials were successfully prepared.The research content is as follows:?1?Nitrogen-doped bamboo porous carbon materials?NC?were prepared,taking bamboo charcoal as a carbon precursor and melamine as a nitrogen source.The electrochemical performance was studied by controlling the carbon-to-base ratio during the activation process.The results showed that the mass specific capacitance was as high as 224 F/g at a current density of 1 A/g,and the specific capacitance was increased by 86.6%relative to the blank sample?BC-1?.After 5000 cycles of charge and discharge at current density of 10 A/g,the initial capacitance retention rate of 93%was still achieved.?2?Using bamboo powder as a carbon precursor,melamine as a nitrogen source,and K₂CO₃ as a pre-activator,a nitrogen-containing functional group was successfully connected to the surface of bamboo powder through physical and mechanical pretreatment,and nitrogen-doped coral-like porous carbon?N-BC?was successfully prepared through two activation processes.During the two-electrode system test,the optimal sample not only showed the high mass specific capacitance?258 F/g at 0.1 A/g?,also had the excellent cycle performance?97.4%of capacitance retention rate after 5000 cycles?.?3?By using corncob as the raw material,the lignin component was efficiently extracted by the sulfite pulping process,and successfully employed to prepare the sulfur-doped spherical porous carbon material?S-PC?after the hydrothermal carbonization and high temperature activation,taking cetyltrimethylammonium bromide?CTAB?as the soft template.When the current density is 0.1 A/g,the specific capacitance is as high as 384 F/g;when the current density is increased to 50 A/g,the specific capacitance can still be maintained at 191 F/g.After 10000 cycles,the initial specific capacitance is maintained at 99.4%,showing excellent stability.