硫在不同碳载体材料中的电化学性能研究

为了探索碳载体材料结构对于硫的电化学性能的影响，本文通过高温固相法将升华硫与石墨烯、导电炭黑、多孔碳等三种不同结构的碳载体材料复合，制备得到硫含量相近的三种硫碳复合材料. 通过电镜扫描、低温氮吸附、X射线衍射等方法，对所制备的硫碳复合材料的结构和硫的分布状态进行了表征和分析. 并进一步对三种复合材料进行了电化学性能测试，结果表明，硫负载到多孔碳中的电化学性能最好，其初始放电比容量达到了1623.2 mA·h·g^-1，循环100周之后，其放电比容量仍能保持在845 mA·h·g^-1. 这主要因为相比于石墨烯的层状结构和导电炭黑的链状结构，多孔碳材料中含有大量的微孔和介孔，负载硫后，与硫分子的接触面积大，活性物质的利用率高，从而提高了硫的电化学性能.

Electrochemical Properties of Sulfur in Different Carbon Support Materials

In order to investigate the effect of carbon structure on electrochemical performance of sulfur/carbon composite in lithium-sulfur battery, in this paper, sublimation sulfur was incorporated into three types of carbon materials, namely, graphene, carbon black and porous carbon. The three sulfur/carbon composites were characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), and X-ray diffraction (XRD) techniques, and their electrochemical performances were also studied. The results showed that the sulfur/porous carbon composite offered an initial discharge capacity of 1623.2 mA·h·g^-1 and remained 845 mA·h·g^-1 after 100 cycles. Compared with graphene and carbon black, the mesopores and micropores in porous carbon improved the utilization of sulfur, contributing to better electrochemical performance of sulfur.