Synthesis and Crystallization of Atomic Layer Deposition β-Eucryptite LiAlSiO<sub>4</sub> Thin-Film Solid Electrolytes
Ryan Sheil, Ya-Chuan Perng, Julian Mars, Jea Cho, Bruce Dunn, Michael F. Toney, Jane P. Chang
Abstract
Atomic layer deposition (ALD) was used to control the stoichiometry of thin lithium aluminosilicate films, thereby enabling crystallization into the ion-conducting β-eucryptite LiAlSiO4 phase. The rapid thermal annealed ALD film developed a well-defined epitaxial relationship to the silicon substrate: β-LiAlSiO4 (12̅10)||Si (100) and β-LiAlSiO4 (101̅0)||Si (001). The extrapolated room temperature ionic conductivity was found to be 1.2 × 10–7 S/cm in the [12̅10] direction. Because of the unique 1-D channel along the c axis of β-LiAlSiO4, the epitaxial thin film has the potential to facilitate ionic transport if oriented with the c axis normal to the electrode surface, making it a promising electrolyte material for three-dimensional lithium-ion microbatteries.