Facile and scalable fabrication of high-energy-density sulfur cathodes for pragmatic lithium-sulfur batteries

Lithium-sulfur battery is garnering much of attention due to its high energy densities, low-cost active material of sulfur and variety of applications in portable electronics. High integrity and consistent qualities of the large-scale sulfur cathode with high energy have to be ensured to construct reliable and practical lithium-sulfur batteries that could supersede advancing lithium-ion batteries. Here, facile and productive approaches are developed to mass-produce functional sulfur hosts and to fabricate large-scale sulfur cathode with high sulfur loading. The functional sulfur host is synthesized by anchoring polyethylenimine at the surface of commercially available carbon at inert conditions with a scale of more than 10 g per batch via simple solution method. Combining the functionalized sulfur host with a polyacrylic acid binder allows high integrity and uniformity of the high sulfur loading cathode to be fabricated in large dimensions. Followed by this approach, the sulfur cathode, 70 x 6 cm(2), is produced with the sulfur loading of > 4.3 mg cm(-2). It is found that 12 wt% of polyethylenimine in the functionalized sulfur host with polyacrylic acid is at optimal condition that presents stable electrochemical performances over 600 cycles.