Improvement of the electrochemical properties of sulfur cathode materials with multiwalled carbon nanotubes

Abstract

In order to improve electronic conductivity and prevent dissolution of sulfur into the electrolyte,composite materials based on elemental sulfur and multiwalled carbon nanotubes(MWCNTs) with high specific surface area and strong absorbability as an inactive additive were prepared by a completely airtight step-wise heat synthesis method.X-ray diffraction,scanning electron microscopy and specific surface area measurements all indicated that elemental sulfur was distributed evenly throughout the MWCNTs.The electrochemical tests showed that the initial discharge specific capacity of an elemental sulfur positive electrode with MWCNTs was 1487.0mAh·g-1 and the utilization of electrochemically active sulfur was 88.9%.The specific capacity remained as high as 913.7mAh·g-1 after 50 cycles which showed that the electrochemical properties of the sulfur cathode with the addition of MWCNTs were remarkably improved.