Immobilizing sulfur in high-density 3D graphene gel for high-performance lithium/sulfur battery

• 作 者: LI Hongfei WANG Xiaomin ZHANG Yuegang YANG Xiaowei
• 机 构: i-LAB,Institute of Nano-Tech and Nano-Bionics,Chinese Academy of Sciences,Suzhou 215123,Jiangsu,Chin
• 出 处: 第一届全国储能科学与技术大会
• 发表日期: 2014年5期

　　Rechargeable lithium/sulfur (Li/S) batteries have attracted great interest in recent years, since sulfur is a promising cathode material with high theoretical specific capacity (1675 mA.h/g) and energy density (2600 W.h/kg), low cost as well as natural abundance in earth.However, there are still some challenges for the application of Li/S batteries, such as the diffusion of lithium polysulfides, volume/morphology changes of sulfur electrode during cycling and the poor electronic conductivity of sulfur, thus leading to low specific capacity and short cycle life.Three-dimensional (3D) graphene was widely used to address these problems through its unique frameworks, which not only increases the conductivity of sulfur, but also confines sulfur and polysulfides into pore structure.However, the micron-sized internal void space could minimize polysulfide dissolution and shuttling just at a certain extent, which couldnt meet the requirements for high-performance Li/S battery.In this work, we improve the electrochemical performance of Li/S battery by immobilizing sulfur in high-density 3D graphene gel.Upon oven-drying, the volume of sulfur-graphene (S-G) hydrogel could be compressed by more than seven times and accordingly, the pores are shrinked and show a high packing density, as shown in Fig.1.Meanwhile, uniform sulfur thin film on graphene nanosheets surface are achieved by a low temperature interfacial growth.