Water-based fabrication of garnet-based solid electrolyte separators for solid-state lithium batteries. Issue 15 (6th July 2020)

• Record Type: Journal Article
• Authors: Ye, Ruijie; Tsai, Chih-Long; Ihrig, Martin; Sevinc, Serkan; Rosen, Melanie; Dashjav, Enkhtsetseg; Sohn, Yoo Jung; Figgemeier, Egbert; Finsterbusch, Martin
• Is Part Of: Green chemistry. Volume 22:Issue 15(2020)
• Page Start: 4952
• Page End: 4961
• Publication Date: 2020-07-06
• Subjects: Environmental chemistry -- Industrial applications -- Periodicals; Environmental management -- Periodicals; 660
• DOI: 10.1039/d0gc01009j
• Languages: English
• ISSNs: 1463-9262

Abstract

Abstract : Garnet-type Li7 La3 Zr2 O12 (LLZ) is regarded as a promising oxide-based solid electrolyte (SE) for solid-state lithium batteries (SSLBs) or other advanced Li-battery concepts like Li–air or Li–S batteries. Abstract : Garnet-type Li7 La3 Zr2 O12 (LLZ) is regarded as a promising oxide-based solid electrolyte (SE) for solid-state lithium batteries (SSLBs) or other advanced Li-battery concepts like Li–air or Li–S batteries. A thin free-standing LLZ sheet can be fabricated by tape-casting and used e.g. as separators in SSLBs, since tape casting is an industrially established process and enables large-scale production of such SEs. However, organic solvents and additives employed in conventional slurry recipes for tape-casting give rise to health and safety concerns and also cause a high cost for solvent recovery. Hence, development of a green, water-based processing route can reduce both manufacturing costs and environmental footprint. In this work, we developed a tape-casting process for LLZ SEs using water as solvent, the water-soluble biopolymer methylcellulose as binder and other eco-friendly polymers as plasticizers. Although a Li + /H + exchange takes place during our procedure, we demonstrate that the Li + /H + exchange reaction is reversible in our procedure and results in the formation of stoichiometric cubic LLZ at the end. The obtained free-standing LLZ sheets with thickness of 150 μm and relative density of approx. 90% offer an ionic conductivity of 0.15 mS cm −1 at room temperature. We thereby prove that it is feasible to use water as dispersion medium and eco-friendly polymer additives for the fabrication of thin garnet-based SE layers.