Antimony-doped SnO₂ microspheres with Controlled Pore size : High Energy density and Cycle stability for Li-ion Battery

Abstract

In this study, the tin oxide (SnO₂) was synthesized as a porous monodisperse structure to be used as an anode active material by overcoming the disadvantages of electrode deterioration due to volume expansion and applied as an anode active material. In order to improve the low conductivity of the tin oxide series, doping of the antimony element was carried out and finally, antimony-doped tin oxide (ATO) was synthesized. Polymerization proceeds in two stages. Polystyrene(PS) is used to make the particle size uniform by using dispersion polymerization, and seed polymerization is carried out on the particle to produce particles having a porous structure to synthesize a final polymer template. Due to the nature of polystyrene, it does not have hydrophilicity, and after acid treatment is carried out to make it hydrophilic, tin/carbon composite is made by diffusing tin ions in water from porous polystyrene particles. When the tin/carbon composite is subjected to firing under air conditions after introducing antimony in ethanol by sol-gel method, monodispersed, porous, antimony-doped tin oxide particles that maintain the shape of the polymeric template are synthesized. The morphology of the particles was confirmed by optical microscope (OM) and scanning electron microscope (SEM), and the porosity of the particles was determined by means of a specific surface area analyzer (BET). It was confirmed that the antimony element was uniformly doped into the particles through X - ray diffraction (XRD) and X - ray spectral analysis. Through this experiment, it has been proved that the structure control of the particles and the doping effect of the element have a significant influence on the cyclability and the rate capability of the active material. The electrochemical properties were evaluated by using SnO2 prepared by the polymer template method as a control and ATO as a comparative group. Reversible capacity was confirmed using a charge/discharge device, and dQ/dV curves were used to confirm the reaction of the active material with lithium ions during charging/discharging. The performance of ATO was greatly improved by comparing cyclability, the rate capability and the conductivity. Through this research, possibility of anode active material of ATO with monodispersed porous structure for improvement of performance of lithium ion battery among next generation eco-friendly energy technology can be expected.