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• CNT@Co 3 O 4-x -P with dual defects of O-vacancy and P-doping is developed. • The construction of O-vacancy mainly promotes polysulfide conversion kinetics. • The phosphorus doped atoms mainly contribute to polysulfide adsorption. • CNT@Co 3 O 4-x -P/S based cell shows excellent specific capacity and cycling stability. Lithium-sulfur (Li-S) battery is considered as a burgeoning energy storage device owing to its high theoretical energy density. However, the shuttle effect and sluggish kinetics of sulfur species during conversion reactions lead to the challenges in attaining commercial application of high-performance Li-S battery. Herein, a double-defect engineering strategy is developed to endow CNT@Co 3 O 4 with favorable effects on Li-S chemistry by introducing oxygen vacancies and phosphorus doped atoms (CNT@Co 3 O 4-x -P). Experimental and theoretical investigations indicate that both enhanced adsorption and conversion of polysulfides can be realized on the surface of CNT@Co 3 O 4-x -P. Taking advantage of the superb adsorption-conversion property of CNT@Co 3 O 4-x -P, the cell achieves a specific capacity of 903 mAh/g with splendid cyclability at 2 C and a high areal capacity of 7.3 mAh cm−2 under the lean electrolyte (E/S = 6 μL E mg−1 S) condition. This work offers a creative approach to implement high-performance Li-S batteries and promotes the application of Li-S batteries. [ABSTRACT FROM AUTHOR]

• The CoO/C nano dodecahedron derived from ZIF-67 possesses high porosity and ample chemical sites for the effective absorption and electrochemical conversion of lithium polysulfides. • The unique intercalated microstructure of graphene sheets penetrating through CoO/C polyhedrons provides continuous and rapid charge transfer between conductive matrix and CoO/C, expediting the redox conversion of lithium polysulfides. • The self-supported N-rGO@CoO/C as sulfur host for Li-S battery can achieve high areal capacity of 10.0 mA h cm−2 at a relatively high sulfur loading of 9.6 mg cm−2. The lithium-sulfur (Li-S) battery is recognized as one of the most advanced batteries with superior theoretical energy density. Nevertheless, the industrial production of lithium sulfur battery is hindered by the insulation of sulfur and the shuttle behavior of soluble polysulfides. Herein, a freestanding Li-S battery cathode with a unique intercalated microstructure by penetrating graphene sheets into CoO/C polyhedrons is developed as an effective polysulfides reservoir (N-rGO@CoO/C). The unique intercalated microstructure offers continuous and rapid charge transport between the conductive matrix of N-rGO and CoO/C, effectively expediting the redox conversion of lithium polysulfides. Meanwhile, the 3D porous network provides accommodation for storing sulfur and adapts to large volume change. As a result, an impressive initial capacity of 1216 mA h g−1 of the cell with N-rGO@CoO/C can be achieved when sulfur proportion and loading reach 72 wt% and 3.5 mg cm−2, respectively. Moreover, the derived Li-S battery possesses an outstanding areal capacity (10.0 mA h cm−2) and excellent cycling stability (capacity retention of 7.47 mA h cm−2 after 150 cycling) even with a very high sulfur loading (up to 9.6 mg cm−2). This study offers a feasible way for the development of self-supporting cathode and high-performance Li-S batteries. [Display omitted] [ABSTRACT FROM AUTHOR]

Lithium-sulfur (Li–S) battery with high theoretical energy density is recognized as a promising energy storage device, while its commercial applications are still hampered by the severe shuttling effect and sluggish kinetics of lithium polysulfides (LiPSs). Heteroatoms doping, which can adjust the electronic configuration and regulate the adsorption and catalytic properties, is realized as an effective strategy to solve the above problems. Herein, sulfur-doped CoP nanoparticles embedded in hollow carbon microspheres (C@S–CoP) is designed and employed as the modification material for separator. The introduction of sulfur atom into CoP leads to enhanced chemisorption for LiPSs and favorable conversion kinetics of sulfur species. In addition, the hollow porous structure of C@S–CoP is beneficial to the penetration of electrolyte and the alleviation of the sulfur species expansion during cycles. Theoretical calculation is further utilized to elucidate the enhanced mechanisms of S–CoP in Li–S chemistry at molecular level. The cell with C@S–CoP-separator delivers a superior rate performance of 761 mAh g−1 at 5C and excellent cyclability over 400 cycles at 2C with a low-capacity decay rate of 0.060%. This work furnishes a feasible strategy to boost the electrochemical performance and promotes the development of functional separators for highly efficient Li–S battery. [Display omitted] • The sulfur atoms are doped into CoP to realize the regulation of electronic structure. • ● The sulfur-doped CoP can enhance the chemical affinity toward LiPSs. • ● The introduction of S atoms into CoP is beneficial to promoting LiPSs conversions. • ● The cells with C@S–CoP modified separator exhibit superior rate performance and cycle stability. [ABSTRACT FROM AUTHOR]