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• Multistage porous structure is designed with 3DOM metal Sn and microporous Co-NC. • Metal Sn as 3DOM skeleton has high conductivity and strong adsorption towards LiPS. • Co-NC provides catalytic conversion and additional chemisorption sites for LiPS. • The hierarchical structure facilitates electrolyte infiltration and LiPS trapping. The practical utilization of lithium-sulfur (Li-S) batteries is obstructed by the shuttle effect and sluggish conversion kinetics of the lithium polysulfides (LiPS). Herein, cobalt nanoparticles embedded N-doped carbon composite (Co-NC) decorated metallic tin with three-dimensionally ordered macroporous (3DOM) structure is designed to deal with these issues. The ordered interconnected macropores of the unique hierarchical structure can provide smooth Li ion transport, and the micro-/mesopores of Co-NC derived from ZIF-67 can trap polysulfides. Additionally, the highly conductive metal Sn as 3DOM skeleton accelerates charge transfer and strengthens the LiPS adsorption. Meanwhile, the embedded Co-NC further facilitates the polar adsorption of LiPS as well as its conversion kinetics. Benefiting from these features, the Co-NC@Sn (NH 3) composite shows a relatively low capacity fading rate of 0.045 % per cycle over 500 cycles at 1 C. Even with raised sulfur loading of 5.2 mg cm−2, a high areal capacity of 4.65 mAh cm−2 can be obtained. Pouch cell fabricated with Co-NC@Sn (NH 3) delivers a high discharge capacity of 701 mAh g−1 under high sulfur loading of 4.50 mg cm−2, implying the superiority of the S/Co-NC@Sn (NH 3) cathode. This work provides a new strategy in efficient sulfur immobilizer design for advanced Li-S batteries development. [ABSTRACT FROM AUTHOR]

• Multistage porous structure is designed with 3DOM CoSn alloy and microporous Co-NC. • 3DOM structure facilitates electrolyte infiltration and the micropores trap LiPS. • Conductive CoSn alloy shows efficient adsorption and catalytic conversion for LiPS. • Co-NC provides catalytic conversion and additional chemisorption sites for LiPS. Reasonable design of porous sulfur cathode can inhibit shuttle effect of lithium polysulfide (LiPS), accelerate redox kinetic and enhance the cycling stability, which is important to the development of lithium-sulfur (Li-S) battery. In this work, a multistage porous composite with three-dimensionally ordered macroporous (3DOM) CoSn alloy and embedded microporous Co decorated N-doped carbon (Co-NC) is rationally designed. The conductive CoSn alloy skeleton exhibits strong polar adsorption and effective catalytic activity towards polysulfide conversion, as well as fast electron transportation. Meanwhile, the 3DOM structure possesses sufficient volume space for ion migration and sulfur expansion. Additionally, the properly embedded Co-NC derived from ZIF-67 can offer abundant micropores and catalytic sites, promoting polysulfide trapping and LiPS conversion kinetics. Accordingly, the Li-S batteries fabricated with 3DOM Co-NC@CoSn exhibit remarkable stability with an ultralow capacity decay of 0.046% per cycle over 500 cycles at 1 C. An impressive areal capacity of about 5.1 mAh cm−2 under high sulfur loading of 6.8 mg cm−2 is also achieved at 0.2 C, with a high capacity retention of 79% over 100 cycles. The pouch cell maintains stable at 0.05 C, and the capacity decay is only 0.29% per cycle. This design and synthesis strategy of cathodes has great prospects in the practical application of Li-S battery. [Display omitted] [ABSTRACT FROM AUTHOR]

• Ordered porous metal oxide embedded dense carbon network interlayer design is proposed. • Porous N,Co-TiO x with embedded NCNT provide effective barrier for LiPS diffusion. • The LiPS catalytic conversion is significantly enhanced. • The interlayer endows the cell with high rate excellent cycling performance. The design of multifunctional interlayer is important for the suppression of lithium polysulfides (LiPSs) shuttle effect in lithium-sulfur (Li-S) batteries. Herein, a multifunctional interlayer fabrication strategy is developed by depositing ordered porous metal oxide embedded with nitrogen-doped carbon nanotubes (NCNT) on the carbon nanofibers (CNFs) skeleton. In this design strategy, three-dimensional ordered macroporous N, Co-doped titanium oxides (N,Co-TiO x) is uniformly deposited on CNFs network, then in-situ growth of NCNT is implemented within the ordered porous oxides framework and CNFs, forming dense-structured adsorption/catalytic multifunctional interlayer (N,Co-TiO x /NCNT@CNFs). The ordered porous N,Co-TiO x together with the implemented NCNT not only provides an effective physical barrier for polysulfides diffusion, but also offers strong chemical interaction with LiPSs adsorption and promoted catalytic conversion kinetics. With these merits, the Li-S battery with N,Co-TiO x /NCNT@CNFs interlayer delivers an impressive rate capability of 638 mAh g-1 at a current density of 5 C. The cell also shows excellent cycling performance with a capacity decay of 0.033 % per cycle after 500 cycles at 1 C. More importantly, the Li-S pouch cells with N,Co-TiO x /NCNT@CNFs interlayer achieve a capacity of 806 mA h g−1 at sulfur loading of 4.0 mg cm−2 after 50 cycles at 0.1 C. This ordered porous metal oxide embedded dense carbon network design provides alternative strategy for the development of high-performance Li-S batteries interlayer. [ABSTRACT FROM AUTHOR]

"Rigid" 3D porous Co-TiO 2 framework in-situ implanted with Co nanoparticles encapsulated N -doped CNTs are designed as efficient dual-functional hosts for both sulfur-cathode and lithium-anode in lithium-sulfur batteries. The polysulfides "shuttle effect" and lithium dendrite growth are simultaneously alleviated thanks to the unique structure and adsorption/catalytic/lithophilic characteristics of the desired material. Excellent cycling stability along with electrochemical properties are achieved by the full lithium-sulfur batteries. [Display omitted] • Co-TiO 2 with a 3DOM structure is used as stable skeleton for both S and Li hosts. • Co@NCNTs are grown in-situ on 3DOM Co-TiO 2 to boost conductivity/catalytic ability. • Interpenetrated NCNTs network boosts the holistic conductivity. • Co NPs improve LiPS/Li+ conversion due to integrated catalytic/lithophilic nature. • Li–S full cell shows super capacity/rate property and stability at lean electrolyte. 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 TiO 2 (Co@NCNTs/Co-TiO 2) as efficient hosts for both sulfur and Li electrodes. Benefiting from the excellent stability of polar Co-TiO 2 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-TiO 2 /Li ‖ Co@NCNTs/Co-TiO 2 /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-TiO 2 /Li anode and Co@NCNTs/Co-TiO 2 /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. [ABSTRACT FROM AUTHOR]

The shuttle effect of lithium polysulfide (LiPS) and slow sulfur reaction kinetics is a key problem hindering the application of lithium-sulfur (Li-S) batteries. To address these problems, herein, a novel multifunctional sulfur cathode design strategy of coating microsporous covalent organic framework (COF) onto metal organic framework (MOF)-derived carbon/transition metal composite is developed. This strategy is proofed by coating a TpPa-1 COFs layer on the UIO-66-NH 2 -derived N-doped Co/Zr-NC, forming core-shell structured Co/Zr-NC@TpPa composite. The Co/Zr-NC core consists of Co nanoparticles and ZrO 2 that offers effective sulfur trapping and catalysis effect for sulfur redox reaction, whereas the microsporous COF shell with polar functional groups further reduces the shuttling of LiPS. The S/Co/Zr-NC@TpPa cathode achieves an initial capacity of 792 mAh g−l at 1 C with 76.4% capacity retention after 500 cycles. More importantly, under the high sulfur loading of 5.10 mg cm−2, it has a high specific surface area capacity of 4.15 mAh cm−2 at 0.2 C. This study provides a promising alternative design strategy for the development of efficient sulfur host in Li-S batteries. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • • 3DOM V-ZnO embedded with ZIF-8-derived NC nanocages was developed as sulfur host. • • V-doped ZnO framework strengthens the chemical adsorption and conversion for LiPS. • • NC nanocages alleviated the LiPS shuttle effect and rendering fast redox reactions. Lithium-sulfur (Li-S) batteries are considered as a promising energy storage device. However, their practical application is still hindered by the unsatisfactory cyclability and slow reaction kinetics. Here, we propose a conductive oxide-based macro-microporous framework, where ZIF-8-derived N-doped carbon (NC) nanocages are embedded within the three-dimensionally ordered macroporous (3DOM) V-doped ZnO matrix, as a high-performance sulfur host for Li-S batteries. The unique framework provides large surface area and high porosity for sulfur accommodation, while the V-doped ZnO skeleton enables a highly conducive substrate for electrochemical reactions. More importantly, such hybrid structure imposes strong fixation and effective catalysis of polysulfides, rendering reversible and rapid sulfur redox reactions. Due to these synergistic effects, the 3DOM NC@V-ZnO/S cathode exhibits an excellent cycling stability with a low capacity fading rate of 0.043 % per cycle during 500 cycles at 1C and a good rate capability of 767.6 mAh g−1 at 3C. Moreover, a high initial areal capacity of 4.4 mAh cm−2 was also achieved under a high sulfur loading of 5.8 mg cm−2 with a low E/S ratio of 4.4 μL mg−1 in coin cells, as well as decent flexibility and stable cycling in Li-S pouch cell configuration. [ABSTRACT FROM AUTHOR]

The polysulfide shuttle is regarded as the most critical challenge that hinders the commercial process of lithium-sulfur batteries (LSBs). Herein, a vanadium-based MIL-47 nanosheets membrane is fabricated on carbon nanotube film for this trouble, which serves as a versatile interlayer material in LSBs. With a good electrolyte wettability, thin thickness and appropriate pore diameter, MIL-47 nanosheets membrane is capable of efficaciously blocking polysulfides and enabling the fast transport of Li ions via the selectively sieving effect. Furthermore, the excellent conductivity and fully exposed catalytic metal centers contribute to enhance the reaction kinetics and sulfur utilization. Therefore, this MOF-based interlayer provides a wonderful capacity of 1044.6 mAh g−1 and a durable cyclic performance with a numbered decay of 0.03 % per cycle for 1000 cycles at 1 C. Even under harsh conditions of high sulfur loading and lean electrolyte, excellent cycle and rate performances are still acquired. This work boosts the development of multi-functional materials in LSBs. [Display omitted] • A conductive MIL-47 nanosheets membrane is prepared on carbon nanotube film. • The MOF membrane is used as an interlayer material in lithium-sulfur batteries. • The MOF membrane can selectively block polysulfides and catalyze their conversion. • Lithium-sulfur batteries deliver impressive cycle stability and rate capability. [ABSTRACT FROM AUTHOR]