100 nm Thin‐Film Solid‐Composite Electrolyte for Lithium‐Ion Batteries. Issue 4 (12th December 2016)

• Record Type: Journal Article
• Authors: Chen, Xubin; Vereecken, Philippe M.
• Is Part Of: Advanced materials interfaces. Volume 4:Issue 4(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2016-12-12
• Subjects: electrochemistry -- oxide interfaces -- thin films; Materials science -- Periodicals; 620.11
• DOI: 10.1002/admi.201600877
• Languages: English
• ISSNs: 2196-7350

Abstract

Abstract : A thin‐film composite electrolyte (CE) with thickness of only 100 nm is fabricated for the first time. The conductivity of the solid electrolyte is 2 × 10 −7 S cm −1 which corresponds to a cell resistance of only 50 Ω cm 2 at this thickness. The electrolyte is composed of a nanoporous thin film, a lithium salt, and a polymer, and is fabricated by a two‐step approach. First, a porous SiO x C y H z film is deposited on the electrode substrate, then the porous structure is filled with a polyethylene glycol (PEG)‐LiX mixture by spin‐coating. The filling ratio of the mesoporous SiO x C y H z is as high as 90% with less than 1% remaining porosity, as determined from ellipsometric porosimetry. The effect of the anion, X −, of the LiX salt as well as the molecular weight of the PEG on the Li + ion conductivity of the CE is investigated. The CE with smaller anion and with lower molecular weight PEG yields the highest conductivity. A functional Li/CE/TiO2 battery is built for demonstration purposes. Abstract : A thin‐film composite electrolyte consisting of a polyethylene glycol‐lithium salt complex in nanoporous SiO x C y H z films is fabricated for the first time. Confinement effects are found in the composite electrolyte. The combination of the composite concept with the thin‐film approach, as demonstrated here, brings a new generic way to fabricate thin‐film solid electrolytes.