Co3O4 Nanocages for High-Performance Anode Material in Lithium-Ion Batteries

Co3O4 nanoparticles have been prepared by a facile strategy, which involves the thermal decomposition of nanoparticles of cobalt-based Prussian blue analogues at different temperatures. The nanoparticles prepared at 450, 550, 650, 750, and 850 degrees C exhibited a high discharge capacity of 800, 970, 828, 854, and 651 mAhg(-1), respectively, after 30 cycles at a current density of 50 mAg(-1). The nanocages produced at 550 degrees C show the highest lithium storage capacity. It is found that the nanocages display nanosize grains, hollow structure, a porous shell, and large specific surface area. At the temperature higher than 650 degrees C, the samples with larger grains, better crystallinity, and lower specific surface area can be obtained. It is found that the size, crystallinity, and morphology of nanoparticles have different effects on electrochemical performance. Better crystallinity is able to enhance the initial discharge capacity, while porous structure can reduce the irreversible loss. Therefore, the optimal size, crystallinity, and cage morphology are suggested to be responsible for the improved lithium storage capacity of the sample prepared at 550 degrees C. The as-prepared Co3O4 nanoparticles also have a potential application as anode material for Li-ion batteries due to their simple synthesis method and large capacity.