title: Dual-protection of a graphene-sulfur composite by a compact graphene skin and an atomic layer deposited oxide coating for a lithium-sulfur battery.
abstract: A reduced graphene oxide (rGO)-sulfur composite aerogel with a compact self-assembled rGO skin was further modified by an atomic layer deposition (ALD) of ZnO or MgO layer, and used as a free-standing electrode material of a lithium-sulfur (Li-S) battery. The rGO skin and ALD-oxide coating worked as natural and artificial barriers to constrain the polysulfides within the cathode region. As a result, the Li-S battery based on this electrode material exhibited superior cycling stability, good rate capability and high coulombic efficiency. Furthermore, ALD-ZnO coating was tested for performance improvement and found to be more effective than ALD-MgO coating. The ZnO modified G-S electrode with 55 wt% sulfur loading delivered a maximum discharge capacity of 998 mA h g(-1) at a current density of 0.2 C. A high capacity of 846 mA h g(-1) was achieved after charging/discharging for 100 cycles with a coulombic efficiency of over 92%. In the case of using LiNO3 as a shuttle inhibitor, this electrode showed an initial discharge capacity of 796 mA h g(-1) and a capacity retention of 81% after 250 cycles at a current density of 1 C with an average coulombic efficiency higher than 99.7%.
authors.affiliation: Department of Chemistry, Tsinghua University, Beijing 100084, People's Republic of China. gshi@tsinghua.edu.cn.
authors.forename: Mingpeng
authors.initials: M
authors.lastname: Yu
authors.forename: Aiji
authors.initials: A
authors.lastname: Wang
authors.forename: Fuyang
authors.initials: F
authors.lastname: Tian
authors.forename: Hongquan
authors.initials: H
authors.lastname: Song
authors.forename: Yinshu
authors.initials: Y
authors.lastname: Wang
authors.forename: Chun
authors.initials: C
authors.lastname: Li
authors.forename: Jong-Dal
authors.initials: JD
authors.lastname: Hong
authors.forename: Gaoquan
authors.initials: G
authors.lastname: Shi