title: Atomic force microscopy studies on molybdenum disulfide flakes as sodium-ion anodes.
abstract: A microscale battery comprised of mechanically exfoliated molybdenum disulfide (MoS2) flakes with copper connections and a sodium metal reference was created and investigated as an intercalation model using in situ atomic force microscopy in a dry room environment. While an ethylene carbonate-based electrolyte with a low vapor pressure allowed topographical observations in an open cell configuration, the planar microbattery was used to conduct in situ measurements to understand the structural changes and the concomitant solid electrolyte interphase (SEI) formation at the nanoscale. Topographical observations demonstrated permanent wrinkling behavior of MoS2 electrodes upon sodiation at 0.4 V. SEI formation occurred quickly on both flake edges and planes at voltages before sodium intercalation. Force spectroscopy measurements provided quantitative data on the SEI thickness for MoS2 electrodes in sodium-ion batteries for the first time.
authors.affiliation: Department of Materials Science and Engineering, University of Maryland , College Park, Maryland 20742, United States.
authors.forename: Steven D
authors.initials: SD
authors.lastname: Lacey
authors.forename: Jiayu
authors.initials: J
authors.lastname: Wan
authors.forename: Arthur
authors.initials: A
authors.lastname: von Wald Cresce
authors.forename: Selena M
authors.initials: SM
authors.lastname: Russell
authors.forename: Jiaqi
authors.initials: J
authors.lastname: Dai
authors.forename: Wenzhong
authors.initials: W
authors.lastname: Bao
authors.forename: Kang
authors.initials: K
authors.lastname: Xu
authors.forename: Liangbing
authors.initials: L
authors.lastname: Hu
keywords: In situ AFM; MoS2; SEI; microbattery; sodium-ion battery; wrinkling