Competing reduction induced homogeneous oxygen doping to unlock MoS_(2)basal planes for faster polysulfides conversion  

作　　者：Da Lei Wenzhe Shang Xu Zhang Yongpeng Li Xiaoshan Shi Shaoming Qiao Qian Wang Qiang Zhang Ce Hao Hui Xu Guohua Chen Gaohong He Fengxiang Zhang 

机构地区：[1]State Key Laboratory of Fine Chemicals,Dalian University of Technology,Dalian 116024,Liaoning,China [2]School of Chemical Engineering,Dalian University of Technology,Panjin 124221,Liaoning,China [3]Shenzhen ApogeeTec Greenergy Co.Ltd.,Shenzhen 518000,Guangdong,China [4]Department of Mechanical Engineering,Research Institute for Smart Energy,The Hong Kong Polytechnic University,Kowloon,Hong Kong 999077,China

出　　处：《Journal of Energy Chemistry》2022年第10期26-34,I0002,共10页能源化学（英文版）

基　　金：financial support from the fund for Creative Research Groups of the National Natural Science Foundation of China(22021005);the Science and Technology Innovation Fund of Dalian(2018J12GX052);the National Natural Science Foundation of China(21776042,22108027);the Fundamental Research Funds for the Central Universities of China(DUT19ZD214);the Shenzhen Science and Technology Program(201908163000519);the GDSTC-Key R&D Project(GDSTC No.2019B090908001)。

摘　　要：The parasitic polysulfides shuttle effect greatly hinders the practical application of lithium sulfur batteries,and this issue can be addressed by promoting polysulfides conversion with catalytic materials such as Mo S_(2).However,the catalytic activity of Mo S_(2)mainly relies on edge sites,but is limited by inert basal planes.We herein report a novel,facile,ethylene glycol enabled competing reduction strategy to dope Mo S_(2)homogeneously with oxygen atoms so that its inert basal planes can be unlocked.Ethylene glycol works as a reducing agent and competes with thiourea to react with ammonium molybdate,leading to insufficient sulfuration of Mo,and consequent formation of O-Mo S_(2).Our theoretical and experimental investigations indicate that the homogeneously distributed O dopants can create abundant adsorption/-catalytic sites in the Mo S_(2)basal planes,enlarge the inter-plane distance to promote ion transport,and thus enhance the catalytic conversion of polysulfides.The oxygen doped Mo S_(2)(O-Mo S_(2))is supported on carbon nanosheets(CNS)and the composite(O-Mo S_(2)/CNS)is employed to modify the separator of Li-S battery.It gives the battery an initial discharge capacity of 1537 m Ah g-1at 0.2 C,and the battery retains a discharge capacity of 545 m Ah g-1after ultra-long 2000 cycles at 1 C,corresponding to a very small cyclic decay rate of 0.0237%.Even under a raising sulfur loading of 8.2 mg cm^(-2),the Li-S battery also delivers a high discharge capacity(554 m Ah g^(-1))with outstanding cycle stability(84.6%capacity retention)after 100 cycles at 0.5 C.Our work provides a novel,facile approach to fabricate highly catalytically active oxygen-doped Mo S_(2)for advanced Li-S batteries.

关 键 词：Competing reduction One-pot Oxygen-doped MoS_(2) Unlocked basal plane Li-S batteries 

分 类 号：TM912[电气工程—电力电子与电力传动] TQ426[化学工程]