Prepation Of Nitrogen And Sulfur Codoped Carbon Microspheres By Solvothermal Method And Its Electrochemical Performance

Heteroatom doped carbon microspheres exhibit excellent electrochemical performance. Recently, heteroatom doped carbon microspheres have drawn widespread research due to its huge application potential in supercapacitors, fuel cells, lithium ion batteries, and other fields. In this paper, nitrogen and sulfur codoped carbon microspheres were successfully fabricated by a solvothermal method and further activated by KOH under high temperature. The samples were systematically characterized by TEM, SEM,Raman spectroscopy, N2 adsorption-desorption, XPS, CV, LSV, galvanostatic charge-discharge and EIS. The details and results are summarized as follows:Firstly, using acetonitrile as nitrogen source, TMTD as sulfur source, nitrogen and sulfur codoped carbon microspheres have been successfully synthesized through solvothermal reaction under 400 ℃ after 24 h. Nitrogen and sulfur codoped carbon microspheres were further activated by KOH under different temperature. As the product of nitrogen and sulfur codoped carbon microspheres activated under 800 ℃,electrochemical testing results indicated that NS-CMSs-800 has the highest oxygen reduction catalytic activity. Compared with the commercially available 20 wt% Pt/C catalyst, the as-prepared NS-CMSs-800 not only exhibits a almost identical pathway of four-electron transfer reaction but also exhibits much better tolerance toward methanol crossover and long-term operation stability for ORR in alkaline medium.Secondly, nitrogen and sulfur codoped carbon microspheres also have been successfully synthesized using sublimed sulfur, thiourea, TMTD as different sulfur source and acetonitrile as nitrogen source by a solvothermal method. The test results show that after activated by KOH under 750 ℃, nitrogen and sulfur codoped carbon microspheres have the hierarchical pore structure, the specific surface area were 397.4-413.8 m²g^-1 and present the superior specific capacitance(242-295 Fg^-1 at 0.1 Ag^-1), outstanding rate capability(the specific capacitance at 10 Ag^-1 were 216-247 Fg^-1) and excellent cyclic stability.Finally, this paper studies the effects of sublimed sulphur in different doses on thepreparation of nitrogen and sulfur codoped carbon microspheres using solvothermal method. Nitrogen and sulfur codoped carbon microspheres were also been successfully synthesized using solvothermal method, when the doses of sublimed sulphur were 1 g, 2 g and 3 g, separately. The yield of nitrogen and sulfur codoped carbon microspheres increased with the increase of the dosage of sublimed sulfur. And the graphitization degree of nitrogen and sulfur codoped carbon microspheres decreased with the increase in the amount of sublimed sulfur. The activated nitrogen and sulfur codoped carbon microspheres present the specific capacitance of 155²24 Fg^-1 at 0.1 Ag^-1, also exhibit outstanding rate capability and excellent cyclic stability.