| Porous carbon has attracted much attention in the field of electrochemistry due to its abundant source,high specific surface area,controllable pore structure and high chemical stability.In this paper,the structural texture and surface properties of porous carbon doped with heteroatoms?S,N,O,nickel and cobalt,etc.?were studied by using biomass materials.In addition to the traditional methods of physical and chemical activation,in-situ template method,electrospinning method and direct carbonization of nickel and cobalt supported by poly ionic liquid were used to prepared different structure characteristics and surface properties of heteroatom-doped porous carbon,and the effects of specific surface area,pore size distribution and surface properties of heteroatom-doped carbon materials in supercapacitors and oxygen reduction reaction?ORR?on fuel cells were systematically investigated.Specific research contents are as follows:?1?Nitrogen-doped porous carbon material was obtained through a facile preparation method from sodium lignosulfonate and 1-allyl-3-methyl imidazolium chloride by simple ion exchange reaction and a following direct carbonization.Without any additional activation agent or template,the inorganic salt Na Cl generated during the precursors'synthesis process was believed to act as the role of self-template and self-activation.The introduction of chloride ionic liquid raised the nitrogen content of the obtained carbon material up to 4.68%and a high yield of SL-CL-700 carbon material up to 34.6%.The effect of carbonization temperature on the structures and electrochemical properties of the prepared carbon were also studied systematically.It was found that the carbon material exhibits superior gravimetric capacitance up to 230F g-1(0.1 A g-1)at the carbonization temperature of 700 oC,good energy density of 7.99W h kg-1 at a power density of 25 W kg-1,and excellent cycling stability of 90.3%after20000 cycles.The work provides a new path for the value-added utilization of biomass coupled with the field of electrochemical energy storage.?2?In this chapter,lignin in corn stalk was extracted by ionic liquid based organic electrolyte([Emim][OAc]/DMSO.In addition,the composite nanofibers of lignin and polyacrylonitrile?PAN?were prepared by electrospinning technology,and their properties were studied as electrode materials of supercapacitor after high temperature pyrolysis.At the current density of 0.1A/g,the capacity of ECNFs-PAN-L was 151F/g,and the capacity retention rate was higher than that of ECNFs-PAN?67.12%>44.91%?at large current discharge,showing good electrochemical properties.?3?In this chapter,Lignosulfonate-based ionic liquids were used as the precursor by loading the double metal Co?Ni to prepare metal-doped biomass porous carbon materials.To explore the influence of oxidation conditions on catalytic activity in the carbonization process,the absolute value of the limit current density of carbon materials after oxidation(2.08 m A cm-2)was significantly higher than that of the unoxidized(1.38m A cm-2).Compared with the carbon materials prepared by the nonmetallic precursor system,the electron transfer number of carbon materials loaded with Co and Ni increased from 2.51 to 3.8.The presence of transition metal transformed the 2 electron reaction with more intermediate products into nearly 4 electron reaction,which greatly reduced the side reaction in oxygen reduction.In addition,the preparation of carbon materials by ionic liquid precursor systems with different organic alkali structures has a certain influence on the metal load,thus affecting the catalytic activity of carbon materials. |
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