title: Dual-Confined Sulfur Nanoparticles Encapsulated in Hollow TiO2Spheres Wrapped with Graphene for Lithium-Sulfur Batteries.
abstract: Lithium-sulfur (Li-S) batteries are attractive owing to their higher energy density and lower cost compared with the universally used lithium-ion batteries (LIBs), but there are some problems that stop their practical use, such as low utilization and rapid capacity-fading of the sulfur cathode, which is mainly caused by the shuttle effect, and the uncontrollable deposition of lithium sulfide species. Herein, we report the design and fabrication of dual-confined sulfur nanoparticles that were encapsulated inside hollow TiO2spheres; the encapsulated nanoparticles were prepared by a facile hydrolysis process combined with acid etching, followed by "wrapping" with graphene (G-TiO2@S). In this unique composite architecture, the hollow TiO2spheres acted as effective sulfur carriers by confining the polysulfides and buffering volume changes during the charge-discharge processes by means of physical force from the hollow spheres and chemical binding between TiO2and the polysulfides. Moreover, the graphene-wrapped skin provided an effective 3D conductive network to improve the electronic conductivity of the sulfur cathode and, at the same time, to further suppress the dissolution of the polysulfides. As results, the G-TiO2@S hybrids exhibited a high and stable discharge capacity of up to 853.4 mA h g-1over 200 cycles at 0.5 C (1 C=1675 mA g-1) and an excellent rate capability of 675 mA h g-1at a current rate of 2 C; thus, G-TiO2@S holds great promise as a cathode material for Li-S batteries.
authors.affiliation: College of Materials Science and Engineering, Hunan University, Hunan Province Key Laboratory for Spray Deposition Technology and Application, Changsha, 410082, P. R. China.
authors.forename: Haining
authors.initials: H
authors.lastname: Fan
authors.affiliation: College of Materials Science and Engineering, Hunan University, Hunan Province Key Laboratory for Spray Deposition Technology and Application, Changsha, 410082, P. R. China.
authors.forename: Qunli
authors.initials: Q
authors.lastname: Tang
authors.affiliation: College of Materials Science and Engineering, Hunan University, Hunan Province Key Laboratory for Spray Deposition Technology and Application, Changsha, 410082, P. R. China. xiaohuachen@hnu.edu.cn.
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Chen
authors.affiliation: College of Materials Science and Engineering, Hunan University, Hunan Province Key Laboratory for Spray Deposition Technology and Application, Changsha, 410082, P. R. China.
authors.forename: Binbin
authors.initials: B
authors.lastname: Fan
authors.affiliation: College of Materials Science and Engineering, Hunan University, Hunan Province Key Laboratory for Spray Deposition Technology and Application, Changsha, 410082, P. R. China.
authors.forename: Shanliang
authors.initials: S
authors.lastname: Chen
authors.affiliation: College of Materials Science and Engineering, Hunan University, Hunan Province Key Laboratory for Spray Deposition Technology and Application, Changsha, 410082, P. R. China.
authors.forename: Aiping
authors.initials: A
authors.lastname: Hu
keywords: cathode materials; graphene; host-guest systems; nanoparticles; polysulfides