Novel Sulfur Host Composed of Cobalt and Porous Graphitic Carbon Derived from MOFs for the High-Performance Li–S Battery

作者：Yanqiu Lü, Yijin Wu, Tian Sheng, Xinxing Peng, Zhenguang Gao, Shaojian Zhang, Li Deng, Rui Nie, Jolanta Światowska, Jun‐Tao Li, Yao Zhou, Ling Huang, Xiao‐Dong Zhou, Shi‐Gang Sun · 发表于：ACS Applied Materials & Interfaces · 年份：2018 · DOI：10.1021/acsami.8b00915 · 被引用次数：67 · 研究领域：Advancements in Battery Materials、Advanced Battery Materials and Technologies、Advanced Battery Technologies Research

A composite consisting of cobalt and graphitic porous carbon (Co@GC-PC) is synthesized from bimetallic metal–organic frameworks and employed as the sulfur host for high-performance Li–S batteries. Because of the presence of a large surface area (724 m 2 g –1 ) and an abundance of macro-/mesopores, the Co@GC-PC electrode is able to alleviate the debilitating effect originating from the volume expansion/contraction of sulfur species during the cycling process. Our in situ UV/vis analysis indicates that the existence of Co@GC-PC promotes the adsorption of polysulfides during the discharge process. Density functional theory calculations show a strong interaction between Co and Li 2 S and a low decomposition barrier of Li 2 S on Co(111), which is beneficial to the following Li 2 S oxidation in the charge process. As a result, at 0.2C, the discharge capacity of the S/Co@GC-PC cathode is stabilized at 790 mAh g –1 after 220 cycles, much higher than that of a carbon-based cathode, which delivers a discharge capacity of 188 mAh g –1 .