硫在不同碳载体材料中的电化学性能研究

Electrochemical Properties of Sulfur in Different Carbon Support Materials

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 m A·h·g-1,循环100周之后,其放电比容量仍能保持在845 m A·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.

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 m A·h·g-1 and remained845 m A·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.