硫/介孔碳复合正极材料的制备与表征

Preparation and Characterization of Sulfur/Mesoprous Carbon Composite Cathodes

以经加热处理的单质硫与由模板法制备的介孔碳合成一种硫/介孔碳复合材料(S/C).结构和电化学性能测试表明,介孔碳能有效提高硫电极的电化学反应活性、限制硫电极中间产物在电解液中的溶解流失,从而使S/C复合电极具有高的比容量、良好的倍率放电性能和稳定的循环性能.在800mA/g的高电流密度下,硫电极的首周放电比容量达到1234mAh/g;循环100周后,比容量仍保持在800mAh/g以上.

A sulfur/mesoporous carbon composite was prepared by thermally treating a mixture of sublimed sulfur and mesoporous carbon. The mierostrueture of the mesoporous carbon was characterized by BET analysis and X-ray diffraction （XRD）. The electrochemical performance of the S/C composite as cathode materials was evaluated by the galvanostatic method. The results confirmed that the mesoporous carbon could not only greatly enhance the electrochemical activity of sulfur electrode, but also effectively confine the diffusion of dissolved polysulfides in organic electrolyte. As a result, the S/C composites showed high capacity, good cycle performance and excellent rate capability. The specific capacity of the S,/C composite was more than 1200 mAh/g for the first discharge,and remained at 800 mAh/g after 100 cycles even at a high current density of 800 mA/g.