Rapid preparation and characterization of oxygen-deficient SnO2 nanobelts with enhanced Li diffusion kinetics

Li surface diffusion kinetics is an important parameter in determining the electrochemical performance of metal oxide electrodes used in Li ion batteries. Here, we investigate this parameter in SnO2 nanobelts. A low cost, simple and facile in-situ calcination method is developed to fabricate highly crystalline SnO2 nanobelts with surface oxygen vacancies using commercially available tin oxide particles as the precursor. The phase composition, morphology and surface characteristics of the SnO2 nanobelts are investigated by several techniques, including the X-ray diffraction and photoelectron spectroscopy, high resolution electron microscopy and electrochemical evaluations. The Li ion surface diffusion coefficients of nanobelts are investigated by impendence spectroscopy and sweep voltammetry measurements; and found to be 1.07 × 10−11 cm2 s−1. Such enhanced Li surface diffusion kinetics as well as significant contribution from pseudocapacitance result in an excellent Li-ion storage performance of SnO2 nanobelts, while the free space between the nanobelts provides morphological stability during prolonged battery cycles.