Superior lithium storage performance of SnO2-modified Co3O4 microflowers self-assembled with porous nanosheets as anode materials in Li-ion batteries

SnO2-modified Co3O4 microflowers self-assembled with porous nanosheets are prepared with the help of solvothermal methods and annealing treatment without using any templates, and ultra-small SnO2 particles are dispersed on the surface of the Co3O4 nanosheets. The structures and physical properties of the as-synthesized samples are characterized by XRD, FESEM, HRTEM, EDS, element mapping, ICP-AES, XPS and N2 adsorption/ desorption measurement. According to the N2 adsorption-desorption isotherm curves, the samples show hierarchically porous structures, and SnO2-modified Co3O4 microflowers have a higher surface area (19.5 m2 g-1 for Co3O4; 30.5 m2 g-1 for SnO2-modified Co3O4). As anode materials in Li-ion batteries, compared with bare Co3O4 microflowers, the SnO2-modified Co3O4 sample delivers higher specific capacity, better rate capability and superior cyclic stability. The discharge capacity of the SnO2-modified Co3O4 sample can reach 767.5 mAh g-1 at 200 mA g-1 after 100 cycles. For even at 3.0 A g-1, the reversible capacity of the composite can still reach 438.8 mAh g-1 after 1000 cycles.