Influence of annealing temperature on microstructure and lithium storage performance of self-templated CuxCo3-xO4 hollow microspheres

Spinel CuxCo3-xO4 (x <= 0.30) hollow microspheres have been readily prepared via a self-templated solvothermal reaction followed by a thermal annealing step. Scanning electron microscopy and transmission electron microscopy images show that the as-prepared hollow microspheres possess an average diameter of similar to 450 nm and a compact, thin, polycrystalline shell with an average thickness of similar to 50 nm. When used as an anode material for lithium ion batteries, CuxCo3-xO4 hollow microspheres exhibit a high lithium storage capacity, which is strongly dependent on the annealing temperature of the CuxCo3-xO4 intermediate. As a result, CuxCo3-xO4 hollow microspheres annealed at 400 degrees C deliver a reversible discharge specific capacity as high as 1187 mA h g(-1) at a current density of 100 mA g(-1) after 50 cycles. Such superior lithium storage performance is derived from the particular microstructure of the shell, which is composed of highly close-connected fine nanoparticles, as well as the resultant better electronic conductivity.