Ordered mesoporous SnO2 with a highly crystalline state as an anode material for lithium ion batteries with enhanced electrochemical performance

Abstract

Ordered mesoporous SnO₂ materials with many regularly ordered pore channels, uniform size distribution, high surface area, highly crystalline state and good structural stability were synthesized via a facile infiltration chemical route. The synthesized ordered mesoporous SnO₂ materials were characterized by X-ray diffraction, Brunauer–Emmett–Teller (BET) method, field emission scanning electron microscopy, and high resolution transmission electron microscopy. Cyclic voltammetry and galvanostatic techniques were utilized to characterize the electrochemical performance of the as prepared SnO₂ samples as anode materials for lithium ion batteries. The ordered mesoporous SnO₂ displays a good rate capability and cycling stability, exhibiting a high specific capacity of up to 557 mA h g⁻¹, and a high coulombic efficiency of up to 98.5%, even after 40 cycles at a high current density of 100 mA g⁻¹. The significant improvement of the electrochemical performance is attributed to the unique ordered mesoporous structure of SnO₂ with a variety of favorable properties. The large surface area endows the synthesized SnO₂ with more lithium storage sites and a large electrode–electrolyte contact area for high Li⁺ ions flux across the interface, a narrow mesopore size distribution is promised to render the liquid electrolyte diffusion into the bulk of the electrode material facile and hence to providing fast transport channels for the solvated Li⁺ ions, and the regularly ordered mesoporous structures are expected to buffer well against the local volume change during the Li–Sn alloying–dealloying reactions, and the interior space allows the volume variation upon insertion–extraction of lithium ions to be better accommodated.