Fine-tuning of stannic oxide anodes' material properties through calcination

Phase pure stannic oxide (SnO2) is an efficient and reliable anode material for Li ion batteries. Understanding of pure SnO2 phase formation with respect to different calcination temperatures (200 degrees C, 300 degrees C, 400 degrees C, 600 degrees C, and 800 degrees C) is attempted in the present work. The samples are prepared by precipitation method and subjected for structural analysis which exhibit varied percentages of crystallinity and crystallite size (17-40 nm) with respect to their calcination temperature varying from 200 to 800 degrees C. Thermal analysis reveal that presence of tin hydroxide composition is unavoidable and formation of pure SnO2 is possible only after 600 degrees C, up to which small amount of weight loss is seen in all the samples. Morphological analyses reveal the spherical grain distribution and grains are dispersed well for samples calcined at high temperatures. Cyclic voltammetry analysis expose that SnO2 with high crystallinity/free from impurity traces are better at electrochemical properties. Also, SnO2 calcined at 800 degrees C exhibit better redox reactions and good cycling ability up to 500 cycles. The charge-discharge analysis shows better specific capacitance for this material, similar to 160 mAhg(-1) in aqueous electrochemical system. On the other hand, electrical conductivity of the sample is 1.9 x 10(-4) Scm(-1) at room temperature as studied by AC impedance spectroscopy.