Flux growth of hexagonal cylindrical LiCoO2 crystals surrounded by Li-ion conducting preferential facets and their electrochemical properties studied by single-particle measurements

In this study, we demonstrate the template-mediated flux growth of one-dimensional LiCoO 2 single crystals surrounded by {104} faces in a hot solution of LiCl-KCl. The reaction and growth processes were characterized by time-dependent X-ray diffraction and scanning electron microscopy. The transformation in the crystal shape from rectangular to hexagonal cylindrical was considered to be directly related to the gradual lithiation of the starting CoO whiskers. Single particle galvanostatic tests of the single-strand LiCoO 2 crystals were carried out. The LiCoO 2 crystals exhibited excellent rate performance and more than 65% of the full capacity was maintained under ca. 370C. These characteristics likely resulted from the exposure of the {104} faces, since they were electrochemically active in layered LiCoO 2 with an α-NaFeO 2 structure and favored fast Li + transportation. This finding will facilitate the development of new materials for advanced lithium ion rechargeable batteries. Hexagonal cylindrical LiCoO 2 crystals surrounded by large {104} planes prepared through template-mediated flux growth exhibit fast Li + transfer and favorable electrochemical performance at high current rates.