Electrochemical properties of yolk-shell and hollow CoMn₂O ₄ powders directly prepared by continuous spray pyrolysis as negative electrode materials for lithium ion batteries

Yolk-shell and hollow CoMn₂O₄ powders are prepared directly by spray pyrolysis from aqueous spray solutions with different concentrations of sucrose. Phase pure tetragonal CoMn₂O₄ powders without impurity phases are prepared even without post-treatment. The powders prepared from a spray solution with a low sucrose concentration of 0.1 M have a hollow structure. The single and double-shelled yolk-shell powders prepared from spray solutions with 0.4 and 0.7 M sucrose, respectively, have high discharge capacities of 519 and 573 mAh g^-1 in the voltage range of 0.01-3 V, respectively, after 40 cycles at a high discharge rate of 800 mA g^-1. However, the thick- and thin-shelled hollow powders prepared from spray solutions without and with 0.1 M sucrose have low discharge capacities of 418 and 276 mAh g^-1 after 40 cycles, respectively. The discharge capacities of the yolk-shell powders are as high as 579, 530, and 443 mAh g^-1 at discharge rates of 1600, 2400, and 3200 mA g^-1 after 40 cycles, respectively.