Conductive Porous Laminated Vanadium Nitride as Carbon-Free Hosts for High-Loading Sulfur Cathodes in Lithium-Sulfur...

Improving the sulfur loading in cathodes is a significant challenge for practical lithium-sulfur batteries. Although carbonaceous sulfur hosts can achieve higher sulfur content and loading, the low tap densities of carbonaceous materials lead to low volumetric energy densities, restricting practical application. Here, conductive porous laminated vanadium nitride (VN) as a carbon-free sulfur host has been successfully developed to construct high tap density, high sulfur loading, and high energy density sulfur electrodes. The laminated stacking multiscale VN featuring interconnected holes possesses high storage space for sulfur loading, achieving high sulfur loading and utilization. VN@S materials' sulfur content and tap density can achieve 80 wt % and 1.17 g cm^-3, respectively. At the sulfur loading of 1.0 mg cm^-2, the VN@S cathode reaches the reversible capacity of 790 mAh g^-1 at 1 C after 200 cycles and 145.2 mAh g^-1 at 15 C after 500 cycles. Precisely, at a high sulfur loading of 12.6 mg cm^-2, the VN@S cathode delivers a reversible capacity of 518.8 mAh g^-1 (485.6 mAh cm^-3) at 0.1 C after 100 cycles.