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

• Published in: ACS applied materials & interfaces Vol. 10; no. 16; pp. 13499 - 13508
• Main Authors: Lu, Yan-Qiu, Wu, Yi-Jin, Sheng, Tian, Peng, Xin-Xing, Gao, Zhen-Guang, Zhang, Shao-Jian, Deng, Li, Nie, Rui, Światowska, Jolanta, Li, Jun-Tao, Zhou, Yao, Huang, Ling, Zhou, Xiao-Dong, Sun, Shi-Gang
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 25.04.2018; Washington, D.C. : American Chemical Society
• Subjects: Chemical Sciences; Inorganic chemistry; Material chemistry; lithium−sulfur batteries; catalysis; cycle stability; in situ UV/vis analysis; bimetallic metal−organic frameworks
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.8b00915

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 m2 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 Li2S and a low decomposition barrier of Li2S on Co(111), which is beneficial to the following Li2S 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.