Synthesis of Carbon Nanotubes on a Shungite Substrate and Their Use for Lithium–Sulfur Batteries

Abstract

A shungite mineral has been used as a support material of catalyst particles to synthesize multiwalled carbon nanotubes (MWCNTs). Raman spectroscopy enabled us to follow the formation of MWCNTs. The morphology of synthesized MWCNTs was investigated by a scanning electron microscope and a transmission electron microscope. As a result of simple heat treatment at 300°C for 3 h in an inert atmosphere, a novel sulfur/multiwalled carbon nanotubes/polyacrylonitrile (S/MWCNT/PAN) composite was synthesized. These methods of obtaining MWCNTs and S/MWCNT/PAN composite based on heat treatment possess the advantages of simplicity and low cost. The introduction of MWCNTs into the composite gives a highly conductive and mechanically flexible framework with an enhanced electronic conductivity and the ability to absorb polysulfides between the Li anode and cathode, which leads to an enhanced cyclability and a higher coulombic efficiency. The cell with this S/MWCNT/PAN ternary composite cathode demonstrates a stable reversible specific discharge capacity of 800 mA·h·g–1 after 50 cycles at a battery C-rate of 0.2 C.