Advanced materials for the 3D microbattery

Out recent achievements in the development of three-dimensional (3D) thin film microbatteries on silicon and on microchannel plates (MCP) are presented. In such 3D microbatteries, the battery sandwich-like structure, including electrodes, electrolyte and current collectors, is deposited conformally on all available surfaces, thereby utilizing the dead volume of the substrate. Thin-film molybdenum oxysulfide and iron sulfide cathodes were deposited galvanostatically. XRD, XPS and TOF-SIMS characterizations indicated that the submicron thick MoOySz films were amorphous, with the stoichiometry of the films varying with depth. Electrodeposited FeSx films have an amorphous, network-like porous structure with nanosize particles. A special flow cell for conformal coating of the perforated substrates was designed. A Li/hybrid polymer electrolyte (HPE)/MoOySz-on-Si 3D half cell ran at i(d) = i(ch) = 10 mu A cm(-2) and room temperature for 100 charge/discharge cycles with 0.1%/cycle capacity loss and 100% Faradaic efficiency. A 3D half cell on MCP exhibited 20 times higher capacity than that of a planar half cell with the same footprint. (c) 2005 Elsevier B.V. All rights reserved.