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The improved physicochemical immobilization and catalytic redox conversion of lithium polysulfides (LiPSs) intermediates are considered to be a desirable solution to enhance the sulfur electrochemistry in lithium-sulfur (Li–S) batteries. Herein, we for the first time, reported the fabrication of the core-shell structure composed of cobalt-doped carbon nano-tube (CNT) assembled polyhedron core derived from the cobalt metal-organic frameworks (Co-MOFs)@graphitized porous carbon aerogel shell as the sulfur reservoir material for Li–S batteries. The obtained sulfur cathodes exhibited excellent electrochemical performance, including a high reversible capacity (939.9 mAh g−1 at 0.1C), outstanding areal capacity (3.35 mAh cm−2 after 50 cycles, under a low electrolyte/8.3 μL m g s − 1 ), and superior cycling stability (the capacity decay rate of 0.087% per cycle after 500 cycles at 1C). The improvement in electrochemical performance could be attributed to the unique core-shell architecture: the multiple polyhedron Co–C cores not only provide a multiple-point catalytic center for LiPS conversion, but also serves as the polar material to inhibit the migrating of polysulfides by chemical interaction; More importantly, the graphitized porous carbon aerogel shell provides a fast transport channel for Li+/e− diffusion, and also sufficient free space for the sulfur reservoir and Li 2 S 2 /Li 2 S deposition. [Display omitted] • Co–C polyhedra reduced the formation of non-graphitic carbon in carbon aerogel. • Core-shell structures provided adequate accommodation capacity for sulfur species. • Multipoint Co–C polyhedron cores accelerated polysulfide redox reaction kinetics. • The S/Co-GC@GPCA cathode delivered outstanding cycling stability. [ABSTRACT FROM AUTHOR]

Methyltrimethoxysilane (MTMS) was used as the precursor and the organosilica aerogel was prepared by an acid-base catalyzed two stage process. To the aqueous system of acid-catalyzed hydrolyzate of MTMS, a kind of hydrophobic organic solvent, cyclohexane, which is insoluble in the aqueous phase was added and dispersed into small droplets with the aid of a high speed homogenizer. Then the reaction mixture was transformed into a gel through base catalyzed condensation. The hydrophobic solvent was pre-embedded in the gel in the form of microcapsules with the condensed MTMS hydrolyzate forming the shell. The pre-embedded hydrophobic solvent reduced the interface tension between the pore liquid and the skeleton solid. Ambient pressure drying of the wet gels produced low shrinkage and gave low density monolithic aerogels consisting of hollow microspheres. [ABSTRACT FROM AUTHOR]

SnP 0.94 nanodot electrocatalysts supported on porous hollow carbon aerogel matrix effectively manipulated electrochemical redox reaction kinetics of sulfur species. [Display omitted] • A synergistic SnP 0.94 @porous hollow carbon aerogel (SnP 0.94 @PHCA) was engineered. • The SnP 0.94 @PHCA could provide adequate accommodation capacity for sulfur species. • Experiment and DFT results confirmed strong adsorption/catalytic activity for LiPSs. • The S/SnP 0.94 @PHCA cathode exhibited an enhanced electrochemical performance. The realization of the high energy density of lithium-sulfur batteries (Li-S) has always been one of the targets pursued by researchers. However, the shuttling effect, dissolution of sulfur/lithium polysulfides (LiPSs), and sluggish redox kinetics in Li-S batteries restricted its long-term application and development. Herein, an advanced sulfur immobilizer composed of SnP 0.94 nanodot electrocatalysts@porous hollow carbon aerogel (SnP 0.94 @PHCA) was synthesized. As expected, the synergistic sulfur host can not only act as a good electrochemical interface but also provide adequate accommodation for active materials to alleviate the LiPS diffusion. More importantly, SnP 0.94 nanodot electrocatalysts supported on the conductive PHCA skeleton effectively expedited the conversion/redox reaction kinetics and also constructed a stronger adsorption system for LiPSs to inhibit the LiPS shuttling behavior. Correspondingly, the SnP 0.94 @PHCA composite endowed the sulfur cathode the outstanding specific capacity of 1017.8 mAh g−1 under a high sulfur loading (2.94 mg cm−2) at 0. 1 C, superior rate performance (579.8 mAh g−1 at 1 C), excellent cycling stability (the capacity decay rate of 0.13% per cycle at 0.5 C), and a high areal capacity of 6.9 mAh cm−2 under starved electrolyte conditions (8.6 μL mg s −1). This work opens up a new direction for constructing the electroactive hosts in Li-S batteries. [ABSTRACT FROM AUTHOR]