Flexible and Hierarchically Structured Sulfur Composite Cathode Based on the Carbonized Textile for High-Performance Li–S Batteries

Carbon hosts have been utilized to obtain composite cathodes with high sulfur loadings for Li–S batteries. However, the complicated synthesis process may hinder their practical applications. Their mechanical and electrochemical properties shall be further improved. Herein, a facile scalable dip-coating process is developed to synthesize a flexible composite cathode with a high sulfur loading. Via the process, a hybrid composed of carbon nanotubes, carbon black, sulfur, and titania nanoparticles is successfully conformally coated on the carbonized textile (c-textile). The formed flexible c-textile@S/TiO2 cathodes with sulfur loadings of 1.5 and 3.0 mg cm–2 can deliver reversible discharge capacities of 860 and 659 mA h g–1 at 2 C, respectively. For the latter one, it can retain 94% of the initial capacity after 400 cycles with a high Coulombic efficiency (∼96%). When its sulfur loading is further increased to 7.0 mg cm–2, its areal capacity reaches 5.2 mA h cm–2. Such excellent performance is ascribed to the synergy effect of the three-dimension conductive hierarchical pore structure and TiO2 additive. They can physically and chemically entrap the soluble polysulfides in the composite cathode. The as-synthesized free-standing composite electrode is of low cost and a high areal capacity, making it suitable for flexible energy storage applications based on Li–S batteries.