Proceedings of Materials for Sustainable Development Conference (MAT-SUS) (NFM22)
Publication date: 11th July 2022
Solid state battery with ceramic electrolyte and Li metal electrode represent next-generation energy storage device with higher energy density and improved safety characteristics compared to current Li-ion battery technology based on organic liquid electrolytes. Solid oxides are good candidates for electrolyte material because of their chemical stability which also allows convenient processing and handling. Garnet-type oxide LLZO (Li7La3Zr2O12) has the potential as an electrolyte material because of its reasonably high Li+-ion conductivity and (electro-)chemical stability. In order to achieve high performance LLZO electrolyte must be fabricated as a thin layer with dense microstructure. In this study LLZO layers were produced by scalable tape-casting method which can be easily integrated into production lines for manufacturing. Ta-doped LLZO electrolyte layers with relative density of 98% and total conductivity of 0.3 mS/cm at room temperature were obtained. The samples were tested electrochemically with Li metal electrodes after appropriate interfacial treatment to achieve good contact between Ta-doped LLZO and Li. Galvanostatic testing at 40 °C resulted in current densities up to 300 µA/cm2 for flat Ta-doped LLZO pellet samples. Higher current density values (>1 mA/cm2) are expected for multilayered samples where thin LLZO electrolyte with lowered ohmic resistance is supported by porous LLZO scaffold layers, resulting in increased interfacial surface area.