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

摘要

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 multrwalled 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.