High-capacity and -kinetics MoS3/r-GO nanosheet cathode for next-generation lithium-ion battery

Abstract

Although sulfur has about five times higher energy density (500 Wh kg-1) than the commercial cathode materials, lithium-sulfur batteries have great difficulty in using practically due to rapid capacity fading by the polysulfide dissolution in the electrolyte1 . Hence, we propose the use of a sulfur-based alternative material such as MoS3/r-GO composite, which can be substituted for the pure sulfur cathodes. In this presentation, we introduce an in situ electrochemical method, which can improve the electrochemical performances of MoS3/r-GO cathode. As is well known, the nanoscale material has high kinetic performance and low volume expansion due to a decreased ion diffusion path and a large surface to volume ratio, respectively. Therefore, to improve the kinetics and stability of the electrode, we intentionally pulverize bulk MoS3 into nanoscale by in situ electrochemical method. Then, the pulverized nanosheets are securely anchored by the oxygen functional group in r-GO, and hence impedes the separation of active materials from the electrode. Consequently, the capacity of the electrochemically treated MoS3/r-GO electrode exhibits a specific capacity of about 900 mAh g-1 at 5.0 A g-1 for 2,500 cycles without capacity fading2.