Ternary porous sulfur/dual-carbon architectures for lithium/sulfur batteries obtained continuously and on a large scale via an industry-oriented spray-pyrolysis/sublimation method
Ternary composites with porous sulfur/dual-carbon architectures have been synthesized by a single-step spray-pyrolysis/sublimation technique, which is an industry-oriented method that features continuous fabrication of products with highly developed porous structures without the need for any further treatments. A double suspension of commercial sulfur and carbon scaffolding particles was dispersed in ethanol/water solution and sprayed at 180 °C using a spray pyrolysis system. In the resultant composites, the sulfur particles were subjected to an ultrashort sublimation process, leading to the development of a highly porous surface, and were meanwhile coated with amorphous carbon, obtained through the pyrolysis of the ethanol, which acts as an adhesive interface to bind together the porous sulfur with the scaffolding carbon particles, to form a ternary composite architecture. This material has an effective conducting-carbon/sulfur-based matrix and interconnected open pores to reduce the diffusion paths of lithium ions, buffer the sulfur volumetric expansion, and absorb electrolyte and polysulfides. Because of the unique chemistry and the structure, the composites show stable cycling performance for 200 cycles and good rate capability of 520 mAh g-1 at 2 C. This advanced spray-pyrolysis/sublimation method is easy to scale up and shows great potential for commercialization of lithium/sulfur batteries.