Multi-Dimensional Composite Frame as Bifunctional Catalytic Medium for Ultra-Fast Charging Lithium–Sulfur Battery

Abstract

The shuttle effect of soluble lithium polysulfides (LiPSs) between electrodes and slow reaction kinetics lead to extreme inefficiency and poor high current cycling stability, which limits the commercial application of Li–S batteries. Herein, the multi-dimensional composite frame has been proposed as the modified separator (MCCoS/PP) of Li–S battery, which is composed of CoS2 nanoparticles on alkali-treated MXene nanosheets and carbon nanotubes. Both experiments and theoretical calculations show that bifunctional catalytic activity can be achieved on the MCCoS/PP separator. It can not only promote the liquid–solid conversion in the reduction process, but also accelerate the decomposition of insoluble Li2S in the oxidation process. In addition, LiPSs shuttle effect has been inhibited without a decrease in lithium-ion transference numbers. Simultaneously, the MCCoS/PP separator with good LiPSs adsorption capability arouses redistribution and fixing of active substances, which is also beneficial to the rate performance and cycling stability. The Li–S batteries with the MCCoS/PP separator have a specific capacity of 368.6 mAh g−1 at 20C, and the capacity decay per cycle is only 0.033% in 1000 cycles at 7C. Also, high area capacity (6.34 mAh cm−2) with a high sulfur loading (7.7 mg cm−2) and a low electrolyte/sulfur ratio (7.5 μL mg−1) is achieved.

Sandwiched cathodes kinetically boosted by few‐layered catalytic 1T‐MoSe2 nanosheets for high‐rate and long‐cycling lithium‐sulfur batteries

“…The superior catalytic activity of 1T-MoSe 2 /CC is well supported by its small Tafel slope values. 25,35 The above results confirm that 1T-MoSe 2 /CC has the best activity to catalytically boost the lithiation/delithiation reaction kinetics, which is responsible for the enhanced discharge capacities at various rates. The Li + diffusion coefficients (D Li ) of the various LSBs were further investigated by cyclic voltammetry.…”

Dual‐Conductive CoSe2@TiSe2‐C Heterostructures Promoting Overall Sulfur Redox Kinetics under High Sulfur Loading and Lean Electrolyte

“…A distinct characteristic peak at ≈7° exhibits in the XRD patterns of Ti 3 C 2 T x MXenes and Co@MXenes precursors. [ 14a,18 ] It is assigned to the (002) plane of MXenes (Figure S4, Supporting Information). For CoSe 2 , TiSe 2 ‐C, and CoSe 2 @TiSe 2 ‐C heterostructures, all of their diffraction peaks ( Figure a) are matched well with the TiSe 2 (JCPDS No.…”

All-Solid-State Thin-Film Lithium-Sulfur Batteries

“…Therefore, efforts for replacing conventional cathodes with high-energy-density materials are mandatory. Lithium-sulfur (Li-S) systems have been widely used in liquid-electrolyte systems due to the outstanding theoretical capacity of S cathode (1675 mAh g −1 ) and remarkably high-energy-density (2,600 Wh Kg −1 ), accompanied by the notorious drawback of the shuttle effect and huge volume changes during cycling [12][13][14][15][16][17]. Many strategies have been devoted to tackle these challenges including designing novel cathodes, modifying separators, and replacing liquid electrolytes with solid-state electrolytes [18][19][20][21][22].…”