Single-wall carbon nanotube network enabled ultrahigh sulfur-content electrodes for high-performance lithium-sulfur batteries

Highlights: • A theoretical prototype of high-sulfur-content cathodes for high-performance lithium-sulfur batteries was proposed. • A highly efficient single-wall carbon nanotube conductive network was constructed for an almost-pure-sulfur electrode. • The high electronic conduction efficiency of the single-wall carbon nanotubes enables high sulfur utilization. • The electrodes enable high real capacities up to 8.63 mA h cm^–2 together with excellent cycling stabilities. Lithium-sulfur (Li-S) batteries are among the most promising candidates for the next-generation energy storage systems. However, challenges regarding the limited sulfur content and areal sulfur loading in the cathode lead to a low areal capacity that cannot even outperform state-of-the-art lithium-ion batteries, which greatly offsets the high-energy advantage of Li-S batteries and further hinders their practical use. Here, we theoretically indicated that the electronic conduction efficiency of the sulfur host nanomaterial plays a crucial role in determining the sulfur content, and a highly efficient single-wall carbon nanotube (SWCNT) conductive network was constructed for our proof-of-concept studies, resulting in an unprecedentedly high sulfur content up to 95 wt%. The interwoven SWCNTs not only provide abundant paths for electron and lithium ion transport, but also facilitate polysulfides trapping during sulfur conversion reactions. As a result, a high areal capacity of 8.63 mA h cm⁻² was obtained with a high areal sulfur loading of 7.2 mg cm⁻², much higher than that of lithium-ion batteries (4 mA h cm⁻²). Our approach demonstrates a new design concept for the electrode materials of high-energy-density lithium-sulfur batteries and could possibly be extended to other electrochemical energy storage systems.