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

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 oxidebased 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.