Realization of room temperature lithium metal battery with high Li+ conductive lithium garnet solid electrolyte

• Published in: Ceramics international Vol. 45; no. 17; pp. 22610 - 22616
• Main Authors: Indu, M.S., Alexander, George V., Deviannapoorani, C., Murugan, Ramaswamy
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2019
• Subjects: Garnet electrolyte; Interface modification; Solid state battery; Solid state battery; Interface modification; Garnet electrolyte
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2019.07.293

Garnet structured solid electrolytes are suitable candidates for lithium metal batteries due to their high lithium ion conductivity and good electrochemical stability. However, large electrode-electrolyte interface resistance still remains a major challenge. Here, we demonstrate realization of room temperature quasi-solid-state battery with high lithium ion conducting Li6.5La3Zr1.75Te0.25O12 (Te-LLZ) as solid electrolyte. To overcome the high interface resistance, we have used gold (Au) interlayer between lithium metal and Te-LLZ. By introducing Au buffer layer, we observed a significant reduction in the interface resistance from 1868 Ω cm2 to 30 Ω cm2 with a stable lithium stripping/platting profile, suggesting a homogeneous lithium ion transport at the lithium/Te-LLZ interface. A quasi-solid-state battery with lithium metal as anode, lithium cobalt oxide (LiCoO2) as cathode and surface engineered Te-LLZ electrolyte with polypropylene (PP) interlayer on the cathode side was demonstrated. The fabricated quasi-solid-state battery delivered an initial discharge capacity of 137 mA h g-1 (50 μA cm-2) and 132 mA h g-1 (150 μA cm-2) at room temperature (25 °C) and 60 °C, respectively.