Porous transition metal oxide scaffold implanted with interpenetrated catalytic network enabling polysulfides restricted and dendrite free Lithium–Sulfur batteries

Abstract

The exploration of porous polar hosts with good structural stability, high catalytic activity, lithophilic nature, and high-conductivity is desirable to solve the dilatory polysulfide redox kinetics and the uncontrolled lithium dendrite growth for efficient and stable lithium–sulfur (Li–S) batteries. Herein, a novel hierarchical metal oxide-based scaffold is developed, in which N-doped carbon nanotubes encapsulated with Co nanoparticles are in-situ implanted within three-dimensional ordered macroporous Co-doped TiO2 (Co@NCNTs/Co-TiO2) as efficient hosts for both sulfur and Li electrodes. Benefiting from the excellent stability of polar Co-TiO2 skeleton, high catalytic activity and lithophilic properties of Co nanoparticles, and high-conductivity of the inter-penetrated NCNTs, the polysulfide conversion kinetics are dramatically boosted, and the dendrite-free lithium electrochemistry is simultaneously accomplished. Cooperatively, the Co@NCNTs/Co-TiO2/Li ‖ Co@NCNTs/Co-TiO2/S full cell expresses high rate capability of 879.66 mAh g−1 at 5C, as well as super cycling stability with a low capacity decay rate of about 0.033 % after 1000 cycles at 3C. Additionally, Li–S pouch cell assembled by Co@NCNTs/Co-TiO2/Li anode and Co@NCNTs/Co-TiO2/S cathode also exhibits a remarkable discharge capacity of 1020.4 mAh g−1 with sulfur loading even reaching 4.5 mg cm−2 after 200 cycles. The present work reveals an effective strategy for developing advanced Li–S batteries dual-functional electrodes.