Excellent dispersibility of single-walled carbon nanotubes in highly concentrated electrolytes and application to gel electrode for Li-S batteries

[Display omitted] •Highly concentrated electrolytes can disperse single-walled carbon nanotubes.•Addition of fluorinated polymers enhances flexibility and mechanical stability.•Highly conductive and flexible composite gels are fabricated.•Li-S batteries using the composite gel cathode exhibit stable cycling performance. The high dispersibility of single-walled carbon nanotubes (SWCNTs) in supporting media is a challenge for maximizing the mechanical and electrical properties of SWCNT-based composite materials. Herein, we demonstrate that highly concentrated lithium-salt electrolytes (HCEs) can disperse SWCNTs without using any other dispersing agents. Incorporating SWCNT-dispersed HCEs into a polymer matrix allows the fabrication of mechanically stable, electronically and ionically (Li+) conductive composite gels. Due to its high electronic conductivity and good dispersion of the electrolyte, the SWCNT/HCE composite gel is a promising electrode material for energy storage devices. As a demonstration, the composite gel is applied as a gel cathode for a Li-sulfur battery by incorporating molecular sulfur into the gel, resulting in stable cycling performance.