为增强单质硫电极的导电性能和抑制活性硫在电解液中的溶解,选用高比表面积、强吸附能力的多壁碳纳米管作为非活性添加剂,通过密封分段加热的方式与单质硫形成复合材料。X射线衍射(XRD)、扫描电子显微镜(SEM)和比表面积(BET)测试均表明单质硫均匀分散到碳纳米管基体中。电化学测试显示添加碳纳米管的硫电极首次放电比容量高达1 487.0mAh.g-1,硫的利用率达到了88.9%,循环50次后比容量还保持在913.7mAh.g-1,较之普通硫电极其电化学性能得到显著改善。
In order to improve electronic conductivity and prevent dissolution of sulfur into the electrolyte,composite materials based on elemental sulfur and multiwalled carbon nanotubes(MWCNTs) with high specific surface area and strong absorbability as an inactive additive were prepared by a completely airtight step-wise heat synthesis method.X-ray diffraction,scanning electron microscopy and specific surface area measurements all indicated that elemental sulfur was distributed evenly throughout the MWCNTs.The electrochemical tests showed that the initial discharge specific capacity of an elemental sulfur positive electrode with MWCNTs was 1487.0mAh·g-1 and the utilization of electrochemically active sulfur was 88.9%.The specific capacity remained as high as 913.7mAh·g-1 after 50 cycles which showed that the electrochemical properties of the sulfur cathode with the addition of MWCNTs were remarkably improved.