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

Abstract

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.