Cobalt nanoparticle-encapsulated carbon nanowire arrays: Enabling the fast redox reaction kinetics of lithium-sulfur batteries

The commercial application of lithium-sulfur batteries is still impeded by the unsatisfying cyclability due to the sluggish reaction kinetics and shuttling effect of polysulfide intermediates. We develop a cobalt nanoparticle-encapsulated carbon nanowire arrays on carbon cloth (CC@Co-CNAs) to enable the fast redox reaction kinetics of the lithium sulfur batteries. The nanowire array-decorated carbon cloth as conductive matrix for sulfur active material could provide highly exposed cobalt nanoparticle active sites, owing to the high length-diameter ratio of the prepared CC@Co-CNAs. The binding affinity between the cobalt nanoparticle-incorporated materials and polysulfide intermediates is enhanced by Co-S bonds, which facilitates the redox reaction of active materials and consequently results in a high sulfur utilization for cathode especially with high sulfur loading. The lithium sulfur battery with CC@Co-CNAs as electrode materials delivers a high initial discharge capacity of 1228 mAh g⁻¹ at 0.25 C, and a high initial discharge capacity of 807 mAh g⁻¹ at 1C with a low capacity fading rate of 0.06% per cycle during 300 cycles. Moreover, a discharge capacity of 958 mAhg⁻¹ at 0.1 C is achieved for the cell even with a corresponding sulfur loading of 6.2 mg cm⁻².