Supramolecular gel-derived NiCo-N-doped porous carbon/CNT hybrid-modified separator enabling enhanced polysulfide redox kinetics and effective shuttle suppression in lithium–sulfur batteries

Abstract

In lithium–sulfur batteries, separator modification is a promising approach to suppress the migration of polysulfides and accelerate reaction kinetics. Herein, we propose a supramolecular gel pyrolysis-derived strategy to synthesize a NiCo-N-doped porous carbon/carbon nanotube hybrid (NiCo-NPC/CNT) for separator modification. The supramolecular gel-derived synthesis produces a three-dimensional (3D) porous carbon architecture that effectively anchors the NiCo alloy nanoparticles. Subsequently, the NiCo alloy nanoparticles act as catalysts to induce the in situ growth of carbon nanotubes during pyrolysis, thereby enhancing electrical conductivity and catalytic activity. These structural features synergistically promote physical adsorption and chemical catalytic ability, thereby accelerating the redox reactions of polysulphides. The NiCo-NPC/CNT-modified separator (NiCo-NPC/CNT@PP) cell exhibited remarkable rate capability (890.4 mAh g⁻¹ at 3C) and cycling stability (649.0 mAh g⁻¹ after 500 cycles at 1C). Furthermore, NiCo-NPC/CNT@PP shows excellent cycling stability under high sulfur loading (11 mg cm⁻²) and lean-electrolyte condition (6 µL mg⁻¹), retaining 269.6 mAh g⁻¹ after 120 cycles at 0.2C.