Atomic Layer Deposited Lithium Silicates as Solid-State Electrolytes for All-Solid-State Batteries

Biqiong Wang; Jian Liu; Mohammad Norouzi Banis; Qian Sun; Yang Zhao; Ruying Li; Tsun-Kong Sham; Xueliang Sun

doi:10.1021/acsami.7b07113

Atomic Layer Deposited Lithium Silicates as Solid-State Electrolytes for All-Solid-State Batteries

ACS Appl Mater Interfaces. 2017 Sep 20;9(37):31786-31793. doi: 10.1021/acsami.7b07113. Epub 2017 Sep 11.

Authors

Biqiong Wang^{1

2}, Jian Liu³, Mohammad Norouzi Banis¹, Qian Sun¹, Yang Zhao¹, Ruying Li¹, Tsun-Kong Sham², Xueliang Sun¹

Affiliations

¹ Department of Mechanical and Materials Engineering, University of Western Ontario , London, Ontario N6A 5B9, Canada.
² Department of Chemistry, University of Western Ontario , London, Ontario N6A 5B7, Canada.
³ Faculty of Applied Science, School of Engineering, University of British Columbia , Okanagan Campus, Kelowna, British Columbia V1V 1V7, Canada.

PMID: 28749129
DOI: 10.1021/acsami.7b07113

Abstract

Development of solid-state electrolyte (SSE) thin films is a key toward the fabrication of all-solid-state batteries (ASSBs). However, it is challenging for conventional deposition techniques to deposit uniform and conformal SSE thin films in a well-controlled fashion. In this study, atomic layer deposition (ALD) was used to fabricate lithium silicate thin films as a potential SSE for ASSBs. Lithium silicates thin films were deposited by combining ALD Li₂O and SiO₂ subcycles using lithium tert-butoxide, tetraethylorthosilane, and H₂O as precursors. Uniform and self-limiting growth was achieved at temperatures between 225 and 300 °C. X-ray absorption spectroscopy analysis disclosed that the as-deposited lithium silicates were composed of SiO₄ tetrahedron structure and lithium oxide as the network modifier. X-ray photoelectron spectroscopy confirmed the chemical states of Li in the thin films were the same with that in standard lithium silicate. With one to one subcycle of Li₂O and SiO₂ the thin films had a composition close to Li₄SiO₄ whereas one more subcycle of Li₂O delivered a higher lithium content. The lithium silicate thin film prepared at 250 °C exhibited an ionic conductivity of 1.45× 10^-6 S cm^-1 at 373 K. The high ionic conductivity of lithium silicate was due to the higher lithium concentration and lower activation energy.

Keywords: X-ray absorption spectroscopy; atomic layer deposition; lithium ion batteries; lithium silicates; solid-state electrolytes.