孔道有序排列高容量S@C复合电极材料的制备及电化学性能

Preparation and Electrochemical Properties of S@C Composite Material with High Capacity and Ordered Alignment of Channels

用氨水对木材进行预处理,去除其中的木质素,再经过高温碳化和活化处理,得到孔道有序排列的多级孔径三维碳材料,于150℃下熔融吸附硫,得到高容量S@C复合电极材料.扫描电子显微镜(SEM)、X射线衍射(XRD)、拉曼光谱及表面吸附实验等测试结果表明,该碳材料呈现各向异性多级孔径的三维结构,孔道与树干生长方向平行有序排列;经过KOH活化后的碳材料孔道内壁上出现较多微孔,从而具有较大的孔容和比表面积.以S@C复合材料作正极组装了锂/硫电池,电化学性能测试结果表明,电池首次放电比容量达1595 mA·h/g,接近于硫电极材料的理论比容量1670 mA·h/g.

The wood was pretreated with ammonia to remove the lignin from the wood,then heated under the protection of inert gas and activated by KOH,the three-dimensional(3D)carbon material with ordered alignment of channels and multi-pores was obtained.After melting and absorbing sulfur in a autoclave at 150℃,a kind of S@C composite electrode material with high capacity was prepared.The composite was characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD),Raman spectroscopy and N 2 adsorption-desorption analysis.The results show that the carbon material has a 3D structure with anisotropic channels and multi-level pores.The channels are arranged orderly in parallel with the growth direction of the tree trunk.In addition,there are many micropores on the inner wall of the carbon material activated by KOH.So the material has high pore volume and specific surface area.Furthermore,the Li/S battery was assembled by using S@C composite as cathode material.The electrochemical results show that the first discharge capacity of the S@C composite electrode material reaches 1595 mA·h/g,which is close to the theoretical specific capacity of sulfur electrode material(1670 mA·h/g).