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Lithium–sulfur (Li–S) batteries are receiving great attention owing to their large theoretical energy density, but the shuttle effect and sluggish kinetic conversion of lithium polysulfides (LiPSs) seriously restrict their practical applications. Herein, various metal single‐atom catalysts immobilized on nitrogen‐doped Ti3C2Tx (M SA/N‐Ti3C2Tx, M = Cu, Co, Ni, Mn, Zn, In, Sn, Pb, and Bi) are successfully prepared by a neoteric vacancy‐assisted strategy, applied as polypropylene (PP) separator coatings to facilitate the fast redox conversion and adsorption of LiPSs for boosting Li–S batteries. Of particular note, among the M SA/N‐Ti3C2Txs, Cu SA/N‐Ti3C2Tx/PP exhibits amazing properties, involving excellent rate performance (925 mAh g−1 at 3 C), superb cycling stability over 1000 cycles, and ultra‐high sulfur utilization even at large sulfur loadings (7.19 mg cm−2; an areal capacity of 5.28 mAh cm−2). X‐ray absorption fine spectroscopy and density functional theory calculations reveal that the asymmetrically coordinated Cu–N1C2 moieties act as the active sites, which possess a higher binding energy and a larger electron cloud with LiPSs than pristine Ti3C2Tx, facilitating the adsorption and kinetic conversion of LiPSs effectively. This work may provide new insights into single atom‐decorated ultrathin 2D materials for enhancing electrochemical performance of advanced batteries for energy storage and conversion. [ABSTRACT FROM AUTHOR]

An optimized structure design of three-dimensional (3D) net-like carbon based Mn3O4 (Mn3O4/CP) composites was realized based on the theory of explosive nucleation and in situ growth. Mn3O4/CP composites have been successfully prepared on a large scale with filter paper adsorbed with manganese(II) oleate as the raw materials using a facile thermal decomposition route. The obtained Mn3O4/CP composite shows a reversible capacity of 1005 mA h g−1 after 90 cycles at a current density of 100 mA g−1, with a remarkably enhanced rate performance and excellent cycling stability compared to the pure Mn3O4 nanostructure which loses most of its capacity within 10 cycles. Even at a current density of 2000 mA g−1, the specific capacity of the Mn3O4/CP composite was still as high as 486 mA h g−1, which is much higher than that of pure Mn3O4 (38 mA h g−1) and the carbon materials (111 mA h g−1). The enhancement of the electrochemical performance could be attributed to the synergy of Mn3O4 enwrapped with the 3D conductive carbon network, thus making it a promising anode material for large-scale energy storage applications. Moreover, this facile and effective synthetic strategy can be further explored as a universal approach for the rapid synthesis of other transition metal oxides and carbon hybrids with subtle structure engineering. [ABSTRACT FROM AUTHOR]

As a promising energy storage system with high specific capacity, lithium‐sulfur (Li−S) battery is striving for a high‐rate and longer lifetime. Whereas the slow redox kinetics and the shuttle effect of polysulfides (PSs) still severely restrict the performance of Li−S batteries. Here, a rational designed ferromagnetic Fe3O4 nanoparticles (FM‐Fe3O4 NPs) modified separator is engineered for Li−S batteries. Moreover, the particle size of FM‐Fe3O4 NPs was tuned to enhance the energy storage performance. Consequently, the cells with FM‐Fe3O4 NPs modified separator achieved a high‐rate and long cycling performance, the specific capacity could reach 672.8 mAh g−1 and a low fading rate (0.028 % per cycle over 700 cycles) at a high rate of 5 C. Experimental results reveals that FM‐Fe3O4 NPs could mitigate shuttle effect, enable efficient redox reactions, and protect the Li anode from severe corrosion. The performance‐enhanced mechanism is further discovered by DFT calculations, the results show that FM‐Fe3O4 NPs act as mediators of redox reaction to block PSs shuttle and dynamically facilitate conversion via changing the molecular structure of PSs and reducing reaction barrier. This work provides a new pathway to improving Li−S batteries based on ferromagnetic materials, which may be generalized to other advanced batteries. [ABSTRACT FROM AUTHOR]