Mesoporous SnO₂ Synthesized with Non-ionic Surfactants as an Anode Material for Lithium Batteries

Mesoporous tin oxides were successfully prepared with the use of non-ionic surfactants, Pluronic 123 (P-123) and Tetronic 908 (T-908). Surface analysis of SnO₂ synthesized with P123 showed an average pore size of ~15 nm. The high-resolution transmission electron microscopy and low-angle X-ray diffraction (XRD) measurements also confirmed their mesoporous nature. The X-ray photoelectron spectroscopy and wide-angle XRD studies revealed that these compounds have a casseritetype SnO₂ structure. The electrochemical properties of these materials as anodes in lithium batteries showed excellent performance with good reversibility. The first-cycle reversible capacity was 1026 mAh/g for the material synthesized with P123. There was a high first-cycle irreversible capacity for SnO₂ synthesized with the use of both non-ionic surfactants. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were employed to study the electrode kinetics during the lithium insertion process in the first cycle. There was a decrease in the charge-transfer resistance with respect to the discharge potential. The synthesis and structural and electrochemical properties of the mesoporous tin oxides are correlated and discussed in detail.