title: LiCoO2 concaved cuboctahedrons from symmetry-controlled topological reactions.
abstract: Morphology control of functional materials is generally performed by controlling the growth rates on selected orientations or faces. Here, we control particle morphology by "crystal templating": by choosing appropriate precursor crystals and reaction conditions, we demonstrate that a material with rhombohedral symmetry-namely the layered, positive electrode material, LiCoO(2)-can grow to form a quadruple-twinned crystal with overall cubic symmetry. The twinned crystals show an unusual, concaved-cuboctahedron morphology, with uniform particle sizes of 0.5-2 μm. On the basis of a range of synthetic and analytical experiments, including solid-state NMR, X-ray powder diffraction analysis and HRTEM, we propose that these twinned crystals form via selective dissolution and an ion-exchange reaction accompanied by oxidation of a parent crystal of CoO, a material with cubic symmetry. This template crystal serves to nucleate the growth of four LiCoO(2) twin crystals and to convert a highly anisotropic, layered material into a pseudo-3-dimensional, isotropic material.
authors.affiliation: Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States of America.
authors.forename: Hailong
authors.initials: H
authors.lastname: Chen
authors.forename: Lijun
authors.initials: L
authors.lastname: Wu
authors.forename: Lihua
authors.initials: L
authors.lastname: Zhang
authors.forename: Yimei
authors.initials: Y
authors.lastname: Zhu
authors.forename: Clare P
authors.initials: CP
authors.lastname: Grey