title: Unconventional pore and defect generation in molybdenum disulfide: application in high-rate lithium-ion batteries and the hydrogen evolution reaction.
abstract: A 2H-MoS2 (H=hexagonal) ultrathin nanomesh with high defect generation and large porosity is demonstrated to improving electrochemical performance, including in lithium-ion batteries (LIBs) and the hydrogen evolution reaction (HER), with the aid of a 3D reduced graphene oxide (RGO) scaffold as fast electron and ion channels. The 3D defect-rich MoS2 nanomesh/RGO foam (Dr-MoS2 Nm/RGO) can be easily obtained through a one-pot cobalt acetate/graphene oxide (GO) co-assisted hydrothermal reaction, in which GO, cobalt and acetate ions are co-morphology-controlling agents and defect inducers. As an anode material for LIBs, Dr-MoS2 Nm/RGO has only a 9% capacity decay at a 10 C discharge rate versus 0.2 C with stable cyclability at the optimized composition (5 wt% RGO to MoS2 and 2 mol% Co to Mo), and significantly achieves 810 mA h g(-1) at a high current density of 9.46 A g(-1) over at least 150 cycles. Moreover, Dr-MoS2 Nm/RGO exhibits superior activity for the HER with an overpotential as low as 80 mV and a Tafel slope of about 36 mV per decade. In contrast to the MoS2 nanosheet/RGO (MoS2 Ns/RGO), which is synthesized in the absence of cobalt ions, Dr-MoS2 Nm/RGO provides high interconnectivity for efficient lithium-ion transport, and rich defects as electrochemically active sites. DFT is used to prove the existence of rich defects due to anion replacement to become a Co-Mo-S atomic structure, releasing inert basal planes to active sites.
authors: SKKU Advanced Institute of Nanotechnology (SAINT) and School of Chemical Engineering, Sungkyunkwan University, Suwon, 440-746 (Republic of Korea).
authors: Kan
authors: K
authors: Zhang
authors: Hwan-Jin
authors: HJ
authors: Kim
authors: Jeong-Taik
authors: JT
authors: Lee
authors: Gee-Woo
authors: GW
authors: Chang
authors: Xinjian
authors: X
authors: Shi
authors: Wanjung
authors: W
authors: Kim
authors: Ming
authors: M
authors: Ma
authors: Ki-jeong
authors: KJ
authors: Kong
authors: Jae-Man
authors: JM
authors: Choi
authors: Min-Sang
authors: MS
authors: Song
authors: Jong Hyeok
authors: JH
authors: Park
mesh_terms: D004220:Disulfides / Q000737:chemistry*; D011211:Electric Power Supplies; D004563:Electrochemistry; D006859:Hydrogen / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D008982:Molybdenum / Q000737:chemistry*; D016062:Porosity
chemical_list: D004220:Disulfides; D006859:Hydrogen; D008982:Molybdenum; C082964:molybdenum disulfide
keywords: electrochemistry; hydrogen evolution reaction; lithium; molybdenum disulfide; nanostructures