title: Amphiphilic surface modification of hollow carbon nanofibers for improved cycle life of lithium sulfur batteries.
abstract: Tremendous effort has been put into developing viable lithium sulfur batteries, due to their high specific energy and relatively low cost. Despite recent progress in addressing the various problems of sulfur cathodes, lithium sulfur batteries still exhibit significant capacity decay over cycling. Herein, we identify a new capacity fading mechanism of the sulfur cathodes, relating to Li(x)S detachment from the carbon surface during the discharge process. This observation is confirmed by ex-situ transmission electron microscopy study and first-principles calculations. We demonstrate that this capacity fading mechanism can be overcome by introducing amphiphilic polymers to modify the carbon surface, rendering strong interactions between the nonpolar carbon and the polar Li(x)S clusters. The modified sulfur cathode show excellent cycling performance with specific capacity close to 1180 mAh/g at C/5 current rate. Capacity retention of 80% is achieved over 300 cycles at C/2.
authors: Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States.
authors: Guangyuan
authors: G
authors: Zheng
authors: Qianfan
authors: Q
authors: Zhang
authors: Judy J
authors: JJ
authors: Cha
authors: Yuan
authors: Y
authors: Yang
authors: Weiyang
authors: W
authors: Li
authors: Zhi Wei
authors: ZW
authors: Seh
authors: Yi
authors: Y
authors: Cui