In Situ Self-Formed Nano Sheet MoS 3 /Reduced Graphene Oxide Material Showing Superior Performance as a Lithium Ion Battery Cathode

• Published in: ACS nano 2018-12
• Main Authors: Chang, Uijin, Lee, JungTae, Yun, Jin-Mun, Lee, Byeongyong, Lee, Seung Woo, Joh, Han-Ik, Eom, KwangSup, Fuller, Thomas F
• Format: Article
• Language: English
• ISSN: 1936-086X
• DOI: 10.1021/acsnano.8b07191

Although lithium-sulfur (Li-S) batteries have 5-10 times higher theoretical capacity (1,675 mAh g ) than present commercial lithium-ion batteries, Li-S batteries show a rapid and continuous capacity fading due to the polysulfide dissolution in common electrolytes. Here, we propose the use of a sulfur-based cathode material, amorphous MoS and reduced graphene oxide (r-GO) composite, which can be substituted for the pure sulfur-based cathodes. In order to enhance kinetics and stability of the electrodes, we intentionally pulverize the micro sized MoS sheet into nano sheets and form an ultrathin nano SEI on the surface using in situ electrochemical methods. Then, the pulverized nano sheets are securely anchored by the oxygen functional group of r-GO. As a result, the electrochemically treated MoS /r-GO electrode shows superior performance that surpasses pure sulfur based electrodes; it exhibits a capacity of about 900 mAh g at a rate of 5C for 2,500 cycles without capacity fading. Moreover, a full-cell battery employing the MoS /r-GO cathode with a silicon-carbon composite anode displays a 3-5 times higher energy density (1,725 Wh kg / 7,100 Wh L ) than present LIBs.