Comparison of SnO2-carbon nanotubes composite and the SnO2-carbon black mixture as an anode for Li-ion batteries

Abstract

This article reports a comparative study on the electrochemical properties between SnO2-carbon nanotubes (CNTs) composite and SnO2-carbon black (CB) mixture. The SnO2-CNTs composite was directly synthesized by a sol-gel method with purified multi-walled carbon nanotubes and tin chloride. The SnO2-CB mixture was obtained by mixing carbon black with the previously prepared SnO2. XRD profiles of SnO2-CNTs and the obtained SnO2 have shown the pure tin dioxide phase for the composite and the mixture. TEM images confirmed that SnO2 nanoparticles with average particle size of 3-20 nm are deposited on the outer surface of carbon nanotubes, while the SnO2 obtained for the mixture indicate larger average particle size than that of in the SnO2-CNTs composite. These samples were used as anode materials for the lithium ion battery. The SnO2-CNTs composite showed an initial charge capacity of 810 mAg−1 which slightly reduced to 500 mAg−1 after 100 cycles. The SnO2-CB mixture had a smaller capacity, i.e., an initial charge capacity of 350 mAg−1, and decreased to 230 mAg−1 after 100 cycles. A reversible capacity at 0.2 Ag−1 was recovered for both samples after the cycling at different current densities, which implies excellent rate performance of the materials.