"Two-dimensional layered transition metal disulphides for effective encapsulation of high-capacity ​lithium sulphide cathodes"

Zhi Wei Seh: Jung Ho Yu, Weiyang Li, Po-Chun Hsu, Haotian Wang, Yongming Sun, Hongbin Yao, Qianfan Zhang & Yi Cui; Nature Communications, 09/25/14.

Additional Authors: Jung Ho Yu, Weiyang Li, Po-Chun Hsu, Haotian Wang, Yongming Sun, Hongbin Yao, Qianfan Zhang & Yi Cui

Abstract:

Fully lithiated ​lithium sulphide (​Li2S) is currently being explored as a promising cathode material for emerging energy storage applications. Like their sulphur counterparts, ​Li2S cathodes require effective encapsulation to reduce the dissolution of intermediate lithium polysulphide (Li2Sn, n=4–8) species into the electrolyte. Here we report, the encapsulation of ​Li2S cathodes using two-dimensional layered transition metal disulphides that possess a combination of high conductivity and strong binding with ​Li2S/Li2Sn species. In particular, using ​titanium disulphide as an encapsulation material, we demonstrate a high specific capacity of 503 mAh g−1Li2S under high C-rate conditions (4C) as well as high areal capacity of 3.0 mAh cm−2 under high mass-loading conditions (5.3 mgLi2S cm−2). This work opens up the new prospect of using transition metal disulphides instead of conventional carbon-based materials for effective encapsulation of high-capacity electrode materials.