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Lithium‐sulfur (Li−S) batteries have been considered one of the most promising energy storage systems, owing to the theoretical specific capacity (1675 mAh g−1) and energy density (2600 Wh g−1). However, it is challenging to solve the shuttling and low reduction kinetics of lithium polysulfides. Hence, the combination of electrospun and hydrothermal treatments acts as an effective strategy to synthesize copper ferrite nanoparticles decorated on nitrogen doped carbon nanofibers (CF/NC). The resultant material is employed as a positive current collector containing Li2S6 catholyte for Li−S batteries. The addition of CF nanoparticles plays a vital role in capturing polysulfides in both physical and chemical adsorption. Besides, promoted sulfur conversion kinetics are obtained due to the excellent catalytic effect, which enabled significantly improved sulfur utilization, high‐rate capability, and cycling stability. Under a 5.75 mg sulfur loading, the cell with CF/NC delivers an excellent cycling stability with 609 mAh g−1 after 300 cycles at 0.2 C. Even at 12.15 mg high sulfur loading, the high initial capacity of the cell is 9.4 mAh at 0.1 C. [ABSTRACT FROM AUTHOR]

[Display omitted] Lithium-sulfur (Li-S) batteries are deemed to have great prospects in the next generation advanced energy storage systems and have been considered in recent years. However, the majority of substrates with both high electronic conductivity and full coverage of adsorption-catalysis synergy are difficult to achieve. Herein, nitrogen functionalized porous carbon nanofibers assembled with nickel ferrite nanoparticles (NFO/NCFs) are successfully prepared by electrospinning combined with hydrothermal treatment, which were applied to current collector containing Li 2 S 6 catholyte and binder-free for Li-S batteries. With its abundant active sites, the NFO/NCFs have a vital role in the adsorption and catalysis of the polysulfides, which further accelerate the redox kinetics. Consequently, Li 2 S 6 catholyte impregnated NFO/NCFs electrode (sulfur loading: 5.09 mg cm−2) exhibits the first discharge capacity of 997 mAh g−1 and maintains at 637 mAh g−1 after 350 cycles at 0.2C, which is superior cycling performance than NCFs. Even at 10.2 mg cm−2 sulfur loading, the composite electrode shows a high area capacity of 8.35 mAh cm−2 at 0.1C and retains 6.01 mAh cm−2 after 150 cycles. The results suggest the multifunction NFO/NCFs that anchor effectively and catalysis are beneficial to realize the goal of the large-scale application for Li-S batteries. [ABSTRACT FROM AUTHOR]

Summary: Lithium‐sulfur (Li‐S) secondary batteries have been limited by the poor cyclic stability, mainly caused by the dissolution polysulfide species into the electrolyte and subsequent irreversible shuttling effect. Recently, addition of the polysulfide adsorbents within sulfur cathode is effectively improving the electrochemical performance. Herein, TiO2 integrated with g‐C3N4 (TiO2@g‐C3N4: TOCN) hybrid was prepared by a facile heating treatment from the precursor of urea and TiO2composites, which used as host material for elemental sulfur (TOCN@S) in Li‐S batteries. The multifunctional TOCN not only reduced the electrochemical resistance but also provided strong adsorption sites to immobilize sulfur and polysulfide. As a result, the TOCN@S cathode with a sulfur content of 74.5 wt% and a sulfur loading of 3.1 mg cm−2exhibits a high initial capability of 804 mAh g−1 at 0.5°C with capacity retention of 67.2% after 500 cycles. Additionally, the composite cathode also possesses excellent high‐rate performance, retaining a remarkable specific capacity of 630 mAh g−1 even at a rate of 2°C. [ABSTRACT FROM AUTHOR]

Summary: The high performance of lithium sulfur (LiS) batteries is the focus of research in recent years. However, the low sulfur loading, shuttling effect in electrolyte, and poor cycling stability limit their applications. Herein, molybdenum carbide nanocrystals embedded carbon nanofibers (Mo2C@CFs: MCCFs) hybrid membrane was prepared in situ on CFs membrane based on carbonthermal reduction of ammonium molybdate. The fibrous MCCFs network is used as the current collector with Li2S6 catholyte solution for LiS batteries, which inhibits the shuttle effect and accelerates kinetics redox reaction. In addition, Mo2C, as electrocatalyst, promotes nucleation of Li2S of the MCCFs substance, which can reduce polarization and increase the specific capacity. As a result, the free‐standing MCCFs@Li2S6 electrode (sulfur loading: 4.74 mg) shows a capacity of 977 mAh g−1 and maintains at 828 mAh g−1 at 0.2 C over 250 cycles, and indicates excellent reversibility and cycling stability. Even with sulfur loading as high as 7.11 mg, the MCCF@Li2S6 electrode exhibits an extremely high capacity of 5.75 mAh. Meanwhile, the Mo2C modified CFs can be effectively retarding the self‐discharge behavior by trapping the polysulfides. Furthermore, the stability improvement of lithium anode state by effectively suppressing the shuttle effect of polysulfide, played an important role in enhancing the electrochemical performance. [ABSTRACT FROM AUTHOR]

• ZFO/NCFs act as self-standing electrode under high sulfur loading. • ZFO as efficient chemical anchor to adsorb polysulfides and inhibit shuttle effect. • ZFO as polysulfides conversion catalyst to accelerate the redox kinetics. Lithium-sulfur (Li-S) battery is regarded as a hotspot in the research field of next-generation energy storage with a theoretical specific capacity of 1675 mAh g−1 and an energy density of 2600 Wh g−1. However, the short cycle life and poor lithium transport kinetics are restricted its real-world applications. Hence, the combination of electrospinning technology and subsequent hydrothermal method acts as an effective strategy to synthesize the ultrafine zinc ferrite nanoparticles decorated on nitrogen functionalized porous carbon nanofibers (ZFO/NCFs). Three-dimensional ZFO/NCFs act as self-standing electrode for Li-S batteries. The presence of ZFO nanoparticles is beneficial for adsorbing lithium polysulfides and inhibiting the shuttle effect. Additionally, ZFO nanoparticles exhibit an excellent catalytic effect of the polysulfides conversion in redox reactions. As a result, the cell of ZFO/NCFs delivers a high initial discharge capacity of 1100.8 mAh g−1 and after 300 cycles the discharge capacity reaches 789.7 mAh g−1 (coulombic efficiency: average 98.7%) at 0.2 C under 5.75 mg sulfur loading. Moreover, the initial capacity of ZFO/NCFs is 10.23 mAh and remains 7.21 mAh at 12.15 mg sulfur loading after 120 cycles. Hence, ZFO/NCFs contribute to adsorption and catalysis, which shows a promising exploration for the design of cathode materials of Li-S batteries. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • CFONC/Li 2 S 6 as binder free electrode for Li-S battery with high sulfur loading. • CFONC as efficient electrocatalyst to facilitate the kinetics of redox reaction. • CFO accelerates homogeneous deposition of Li 2 S on the surface of substrate. • CFONC inhibits the shuttle of polysulfides and thus protects the lithium anode. Lithium sulfur (Li-S) batteries have been paid more attention to meet the demand of high capacity energy storage. However, most substrates applied to electrodes, which have both high conductivity and full coverage of adsorption-catalysis synergies, are difficult to achieve. Herein, the combination of electrospinning and hydrothermal method is developed to fabricate the composite membrane of ferri-based spinel CoFe 2 O 4 (CFO) loaded nitrogen doped carbon nanofibers (CFONC) applied to positive current collector with Li 2 S 6 catholyte and binder-free of Li-S batteries. Benefiting from the improved catalytic performances in redox reaction of lithium polysulfides due to the abundant active sites which originate from CFO, the CFONC composite with S loading of 4.74 mg exhibits an initial specific discharge capacity of 1096 mAh g−1 at 0.2 C and a high specific discharge capacity of 681 mAh g−1 after 500 cycles with a capacity decay as small as 0.076% per cycle. Even with S loading of 7.11 mg, the cell of CFONC delivers a high initial capacity of 6.1 mAh and maintains 4.8 mAh after 300 cycles. The results show that the efficient chemical anchoring polysulfides and catalyzing redox reaction by multifunctional CFONC composites is a feasible strategy for the large-scale application of lithium sulfur batteries with high performance in the future. [ABSTRACT FROM AUTHOR]