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Lithium-sulfur (Li-S) battery possess the advantage of high specific energy but suffer from unstable cyclic performance due to the sluggish liquid-solid conversion kinetics causing severe lithium polysulfides (LiPS) shuttling. Designing multifunctional electrocatalysts with improved activity and abundant active sites to regulate the dynamics for sulfur electrochemistry is still a significant challenge. Herein, we proposed a thiourea assisted pyrolysis combined with hard template method to synthesize cobalt single atoms co-coordinated by N and S atoms embedded hollow carbon spheres (Co-NS-HCS) as a novel sulfur host. The Co-NS-HCS mainly consists of well-dispersed Co-N 3 S-C center sites where Co is co-bonded by N and S atoms. Systematical characterizations revealed that the Co-NS-HCS exhibit improved SRR electrocatalytic properties with higher exchange current density and larger electron transfer number than that of Co-N-HCS. When equipped in sulfur cathodes, the S@Co-NS-HCS exhibits superior rate performance (925 mAh g−1 at 2 C), long cycle stability (69.1% of capacity retention after 500 cycles at 1 C). Moreover, the assembled Li-S pouch type cell also exhibits competitive cyclic performance that work stably for 100 cycles at 0.1 C with a high capacity retention of 84.7%. This work furnishes a feasible scheme for the rational design of single atoms catalysts with improved electrocatalytic activity for sulfur cathodes based on the coordination environment regulation strategy. Cobalt single atoms co-coordinated by N and S atoms embedded hollow carbon spheres is synthesized as a highly efficient sulfur electrocatalyst to boost both the sulfur reduction and Li 2 S oxidation for advanced Li-S batteries with improved cyclic performance. [Display omitted] • Co single atoms coordinated by N/S are designed as efficient electrocatalysts. • The redox reaction kinetics of LiPS are boosted through S modulation. • The shuttle effect of LiPS is efficiently suppressed. • A high capacity retention of 84.7% is obtained in Li-S pouch cell. [ABSTRACT FROM AUTHOR]

• Low absolute TCR values could be achieved in the range of x = 0.4–0.8 and zero TCR could be realized around 0.6

The first principle calculation was conducted to predict the effect of Co2+ ion substitution on the crystal structure, electron density, formation energy and vibration properties of Li 2 MgSiO 4 ceramic. All the samples were synthesised through the solid-state reaction method. Variations in sintering and dielectric properties were analysed through X-ray diffraction, scanning electron microscopy, network analysis, Raman spectrometry, thermomechanical analysis and simultaneous thermal analysis. Bond length, bond population and electron distribution in a MgO 4 tetrahedron were modified due to the substitution of Mg2+ ion by Co2+ ion. The densification temperature was lowered from 1250 °C to 1050 °C with the addition of 5% (molar ratio) Co2+ ions. The sintering window was put forward slightly, and the vibration property was changed. The densification level and microwave dielectric properties were improved accordingly at following conditions: ε r = 5.75, Q × f = 26,500 GHz at 16 GHz, τ f = −9.4 ppm/°C and relative density = 95.2%. The dielectric and sintering properties of Li 2 MgSiO 4 ceramic could be enhanced with the substitution of Mg2+ ion by Co2+ ion. Image 1 • The first principle calculation was performed to expect crystal variation. • The solid-state reaction experiment was done to verify the result of calculation. • Lattice distortion could improve the densification level and dielectric properties. • The sintering temperature has been lowered due to lattice distortion. [ABSTRACT FROM AUTHOR]