Preparation of Highly Oriented Porous LiCoO2 Crystal Films via Li-Vapor Crystal Growth Method

Abstract

To construct better Li-ion-based batteries, highly oriented porous LiCoO2 crystal film is urgently needed for an active positive electrode. In this study, we prepared such a crystal film via the Li-vapor crystal growth method, which involves a simple reaction between the CoO substrate and Li vapor. Highly crystalline LiCoO2 particles 2–3 μm in size were grown on the CoO substrate surface with strong relation of their orientation. The ⟨110⟩- and ⟨018⟩-oriented LiCoO2 particles, which are preferable for Li-ion conduction, were generated on the CoO(110) substrate. On the CoO(111) substrate, LiCoO2 particles were grown with not only the ⟨003⟩ orientation but also the ⟨012⟩ orientation, suggesting that the crystal growth should follow the three-dimensional structure of the CoO and LiCoO2 lattice. Both the prepared LiCoO2 films from the CoO(110) and CoO(111) substrates exhibited stable and superior electrochemical properties for Li-ion battery cycling, indicating that the films will be useful for high-performan...