3D-printed channel-aligned core-sheath architecture with high sulfur loading for kinetics-enhanced Li–S battery

Abstract

Sluggish kinetics in thick cathode with high sulfur (S) loading will lead to low active material utilization and fast capacity decay, thus hampering the practical applications of Li–S batteries. To tackle such issue, a slightly thickness-dependent cathode of activated carbon (AC)-S/single-walled carbon nanotube (SWNT)@SWNT with fast reaction kinetics is constructed via continuously printing core-sheath filaments. Such micro-filaments are composed of vertically aligned “thin AC-S/SWNT” in core layer and porous SWNT-strengthened shell layer, which constructs an appealing well-interconnected porous 3D architecture ensuring fast ion/electron/mass transport throughout the whole printed matrix, effectively expediting electrochemical kinetics even under a high S loading. Moreover, the SWNTs located in shell layer and intercalated in-between AC-S phase in core layer crosslink well for acting as the functional interlayer to suppress polysulfide shuttling, thereby enabling high S utilization. As a result, the 3D-printed thick AC-S/SWNT@SWNT cathode delivers outstanding gravimetric/areal capacity (752 mAh g−1/6.41 mAh cm−2 at 0.5C) and cycling performance under high S loading of 8.6 mg cm−2.