Flexible free-standing cathode enabled via multifunctional Mo₂C for high sulfur loading lithium–sulfur batteries

A free-standing and flexible sulfur host material composed of Mo₂C nanoarrays growing on the surface of carbon cloth (Mo₂C/CC) is designed for the binder-free cathode of the Lithium-sulfur (Li–S) batteries. The carbon cloth substrate is flexible together with the conductive bottlebrush-like Mo₂C, this host material can provide more active sites and a large inner space to accommodate the volume expansion of sulfur to Li₂S₂/Li₂S. The electric conductive Mo₂C nanoarrays can not only adsorb the polysulfides through forming Mo–S bonds to inhibit the shuttle of lithium polysulfides (LiPSs), but also can boost the electron transfer and promote the direct conversion of the LiPSs to Li₂S₂/Li₂S on their surface. As a result, the sulfur cathodes based on the Mo₂C/CC host material exhibit an impressive specific capacity of 1213 mA h g^-1 at 0.1 C, maintain a long-term cyclability with a decay of 0.011% per cycle. More remarkably, excellent capacity of 8.57 mA h cm^-2 can be attained with a high sulfur loading (10.8 mg cm⁻²) benefit from the 3D nanoarrays structure of the Mo₂C/CC host material. Meanwhile, a pouch cell based on Mo₂C/CC@S cathode can cycle steadily.