Electrochemical performance of electrospun lotus-root-structure porous multichannel carbon nanotubes for lithium-sulfur battery applications

Lotus-root-structure porous multichannel carbon nanotubes with sidewalls are used in sulfur/carbon (P-MCNT) composites as a sulfur carrier for Li-sulfur (Li-S) batteries. P-MCNT is prepared by a simple electrospinning method using coaxial needles, followed by heat treatment and etching. P-MCNT developed multichannel inner pores of different sizes in an axial direction when different amounts of polymethyl methacrylate (PMMA) were added. The sidewall-holes are prepared by adding SiO2 to the electrospinning solution followed by etching. As the porosity increases, the sulfur content reaches a maximum of 78 wt%. The sulfur/P-MCNT composite for Li-S batteries exhibits superior performance with a high initial discharge capacity of 1315 mAh g(-1) and maintained satisfactory cyclability. This superior performance was ascribed to the morphology of the P-MCNT, which both captured sulfur and restricted its loss during the charge-discharge process. In addition, the introduction of more pores into the carbon material facilitated the diffusion of lithium ions into the electrodes and improved the interfacial charge transfer. (c) 2020 Elsevier B.V. All rights reserved.