Dual Core−Shell-Structured S@C@MnO2 Nanocomposite for Highly

Stable Lithium−Sulfur Batteries

Lubin Ni,* Gangjin Zhao, Guang Yang, Guosheng Niu, Ming Chen, and Guowang Diao*

School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, Jiangsu, People’s Republic of China.

Abstract:Lithium−sulfur (Li−S) batteries have currently excited worldwide academic and industrial interest as a nextgeneration high-power energy storage system (EES) because of their high energy density and low cost of sulfur. However, the commercialization application is being hindered by capacity decay, mainly attributed to the polysulfide shuttle and poor conductivity of sulfur. Here, we have designed a novel dual core−shell nanostructure of S@C@MnO₂nanosphere hybrid as the sulfur host. The S@C@MnO₂nanosphere is successfully prepared using mesoporous carbon hollow spheres (MCHS) as the template and then in situ MnO₂growth on the surface of MCHS. In comparison with polar bare sulfur hosts materials, the asprepared robust S@C@MnO₂composite cathode delivers significantly improved electrochemical performances in terms of high specific capacity (1345 mAh g−1 at 0.1 C), remarkable rate capability (465 mA h g−1 at 5.0 C) and excellent cycling stability (capacity decay rate of 0.052% per cycle after 1000 cycles at 3.0 C). Such a structure as cathode in Li−S batteries can not only store sulfur via inner mesoporous carbon layer and outer MnO₂shell, which physically/chemically confine the polysulfides shuttle effect, but also ensure overall good electrical conductivity. Therefore, these synergistic effects are achieved by unique structural characteristics of S@C@MnO₂nanospheres.

ACS Appl. Mater. Interfaces 2017, 9, 34793−34803

文章链接:http://pubs.acs.org/doi/10.1021/acsami.7b07996