• 文献标题:   Lithium Sulfide (Li2S)/Graphene Oxide Nanospheres with Conformal Carbon Coating as a High-Rate, Long-Life Cathode for Li/S Cells
  • 文献类型:   Article
  • 作  者:   HWA Y, ZHAO J, CAIRNS EJ
  • 作者关键词:   lithium batterie, sulfur, energy storage, lithium sulfide, cathode, graphene oxide
  • 出版物名称:   NANO LETTERS
  • ISSN:   1530-6984 EI 1530-6992
  • 通讯作者地址:   Univ Calif Berkeley
  • 被引频次:   86
  • DOI:   10.1021/acs.nanolett.5b00820
  • 出版年:   2015

▎ 摘  要

In recent years, lithium/sulfur (Li/S) cells have attracted great attention as a candidate for the next generation of rechargeable batteries due to their high theoretical specific energy of 2600 W.h kg(-1), which is much higher than that of Li ion cells (400-600, W.h kg(-1)). However, problems of the S cathode such as highly soluble intermediate species (polysulfides Li2Sn, n = 4-8) and the insulating nature of S cause poor cycle life and low utilization of S, which prevents the practical use cif Li/S cells. Here, a high-rate and long-life Li/S cell is proposed, which has a cathode material with a core shell nanostructure comprising Li2S nanospheres with an embedded graphene oxide (GO) Sheet as a core material and a conformal carbon layer as a shell. The conformal carbon coating is easily obtained by a unique CVD coating process using a lab-designed rotating furnace without any repetitive steps. The Li2S/GO@C cathode exhibits a high initial discharge capacity of 650 mA.h g(-1) of Li2S (corresponding to the 942 mA.h g(-1) of S) and very low capacity decay rate of only 0.046% per cycle with a high Coulombic efficiency of up to 99.7% for 1500 cycles when cycled at the 2 C discharge rate.