Low temperature molten salt preparation of nano-SnO2 as anode for lithium-ion batteries

• Nano-SnO2 was prepared at low temperature at 180 °C using molten salt method.
• XRD studies shows phase pure tetragonal type structure.
• Negligible capacity retention (92%) was noted up to 50 cycles in the voltage range, 0.005–1.0 V.

We conduct the synthesis of nano-sized tin oxides by the one-pot molten salt method at low temperature. A sample of SnO2 is obtained by heating a mixture of tin (II) chloride, lithium hydroxide and lithium nitrate at 180 °C. The nano-sized SnO2 powder is characterized using the techniques of X-ray diffraction, Brunauer–Emmett–Teller surface area analysis, scanning and transmission electron microscopy and density analysis. The electrochemical properties are analysed using galvanostatic cycling and cyclic voltammetry. The results show that the SnO2 prepared is a single phase material and shows reversible capacities of 471 and 767 mA h g−1 in the voltage ranges 0.005–1.0 V and 0.005–3.0 V vs. Li respectively, at a current rate of 100 mA g−1. Reduction of Sn4+ to Sn at characteristic cathodic peak potentials is observed in the initial and subsequent cycles of cathodic scan. Alloying and de-alloying reactions of Sn are observed at ~0.25 and ~0.5 V vs. Li in the voltage range 0.005–1.0 V, and the formation of Sn to SnO and SnO2 is observed in the voltage range 0.005–3.0 V vs. Li. Lower capacity fading is observed when cycled in the voltage range 0.005–1.0 V as compared to 0.005–3.0 V.

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