CoO/Co-Activated Porous Carbon Cloth Cathode for High Performance Li-S Batteries.

Li-S batteries are one of the most promising candidates for the next generation of batteries because of their high theoretical specific capacity of 1675 mA h g-1 . However, the dissolution of polysulfide causes severe capacity fading during cycling. Herein, a 3 D CoO/Co-activated free-standing porous carbon fiber cloth (CoO/Co@PCF) is designed to suppress polysulfide diffusion from the cathode. The metallic Co and polar CoO can anchor polysulfide through Co-S ionic bonding and the pores of the carbon cloth can provide abundant active sites for electrochemical reactions. Specifically, sulfur in the cathode is loaded by sulfur vapor deposition, which is scalable for fabrication and adjustable to the sulfur-loading amount. The CoO/Co@PCF cathode with sulfur loading of 3 mg cm-2 displays high discharge capacities of 1214.2 and 684.3 mA h g-1 at 0.1 and 2 C, respectively. When the sulfur loading is increased to 5.4 mg cm-2 , low capacity fading of 0.075 % per cycle over 100 cycles at 0.5 C is still observed.