Shape control of CoO and LiCoO2 nanocrystals

Abstract

Shape control of nanocrystals has become a significant subject in materials science. In this work, we describe a convenient way to achieve morphology-controllable synthesis of CoO nanocrystals including octahedrons and spheres as well as LiCoO 2 polyhedrons and spheres. In particular, we explain the formation of CoO octahedrons exposing only high-energy (111) facets using theoretical calculations; these should also be a useful tool for directing future face-controlled preparation of other nanocrystals. More importantly, the as-obtained LiCoO 2 nanocrystals showed different electrochemical performance depending on their morphology, indicating that Li-insertion/deintercalation dynamics might be crystal face-sensitive.

LiMn2O4 microspheres: Synthesis, characterization and use as a cathode in lithium ion batteries

“…For example, Wan's group has calculated that a reduction of diffusion length from 10 μm (the typical particle size of commercial electrode materials) to 100 nm, results in a decrease in the mean diffusion time from 5000 to 0.5 s [14]. Many reports have also demonstrated that smaller particles of electrode materials have shorter diffusion lengths for Li + , higher electrode/electrolyte contact areas, and better accommodation of the strain than common micron-sized materials [15][16][17][18][19].…”

CoO nanocrystals as a highly active catalyst for the generation of hydrogen from hydrolysis of sodium borohydride

“…A calculation on different surfaces of cubic CoO indicates that the surface energy of (111) facets is higher than other low-index facets (e.g. (100) and (110) facets) [19]. Therefore the absorbed oleylamine molecules may protect {111} facets and eventually lead to the formation of octahedron nanocrystals with eight exposed {111} facets.…”

“…For example, Nam synthesized CoO nano cubes and studied the electrochemical behaviors [16]. Wang et al reported the synthesis of octahedral CoO nanocrystals with sizes of 200 nm or even larger and characterized the electrochemical performance [19]. Zhang et al prepared CoO nanocrystals with various morphologies by turning surfactant concentration [22].…”

Facile synthesis of LiCoO2 nanowires with high electrochemical performance

“…Thus various nanostructures of LiCoO 2 , including nanoparticles [9,10], nanoplates [11] and nanospheres [12] have been reported. However, onedimensional nanomaterials like nanowires, nanorods, nanotubes and nanobelts have only rarely been reported.…”