Ordered Mesoporous Carbon Grafted MXene Catalytic Heterostructure as Li-Ion Kinetic Pump toward High-Efficient Sulfur/Sulfide Conversions for Li–S Battery

Abstract

Lithium–sulfur (Li–S) batteries exhibit unparalleled theoretical capacity and energy density than conventional lithium ion batteries, but they are hindered by the dissatisfactory “shuttle effect” and the sluggish conversion kinetics owing to the low lithium ion transport kinetics, resulting in rapid capacity fading. Herein, a catalytic two-dimensional heterostructure composite is prepared by evenly grafting mesoporous carbon on the MXene nanosheet (denoted as OMC-g-MXene), serving as interfacial kinetic accelerators in Li–S batteries. In this design, the grafted mesoporous carbon in the heterostructure can not only prevent the stack of MXene nanosheets with the enhanced mechanical property but also offer a facilitated pump for accelerating ion diffusion. Meanwhile, the exposed defect-rich OMC-g-MXene heterostructure inhibits the polysulfide shuttling with chemical interactions between OMC-g-MXene and polysulfides and thus simultaneously enhances the electrochemical conversion kinetics and efficiency, as fully investigated by in situ/ex situ characterizations. Consequently, the cells with OMC-g-MXene ion pumps achieve a high cycling capacity (966 mAh g–1 at 0.2 C after 200 cycles), a superior rate performance (537 mAh g–1 at 5 C), and an ultralow decaying rate of 0.047% per cycle after 800 cycles at 1 C. Even employed with a high sulfur loading of 7.08 mg cm–2 under lean electrolyte, an ultrahigh areal capacity of 4.5 mAh cm–2 is acquired, demonstrating a future practical application.

Recent Progress for Concurrent Realization of Shuttle‐Inhibition and Dendrite‐Free Lithium–Sulfur Batteries

“…Accordingly, among the various candidates, lithiumsulfur (Li-S) batteries have attracted extensive attention in the last few decades because of their numerous advantages, such as extremely high theoretical capacity (sulfur: 1675 mAh g −1 ), energy density (2600 Wh kg −1 ), low cost, abundance, and environmental friendliness. [4][5][6][7][8][9][10][11][12] Despite these advantages, realizing the practical application of Li-S batteries remains a great challenge. In particular, S cathodes suffer from some severe problems.…”

Regulating Fe Aggregation State via Unique FeNV Pre‐Coordination to Optimize the Adsorption‐Catalysis Effect in High‐Performance Lithium‐Sulfur Batteries

“…As shown in Figure 4b, the S 2p spectra could be deconvoluted into five peaks, which are ascribed into S-metal bonds, terminal S in LiPSs (S T ), bridged S in LiPSs (S B ), thiosulfate and polythionate, respectively. [55] The existence of S-metal bonds indicates that a small quantity of LiPSs is chemically conjunct on the SA-Fe/VN@NMC. [56] The formation of thiosulfate (S 2 O 3 2− ) could be derived from the reaction between SA-Fe/VN@NMC and LiPSs while the polythionate (O 3 S 2 -(S) x-2 -S 2 O 3 ) originated from the conversion between thiosulfate and LiPSs.…”

Hollow Structure Co1–xS/3D-Ti3C2Tx MXene Composite for Separator Modification of Lithium–Sulfur Batteries

“…The dual-function MXene composite catalyst obtained by cationic doping can be used as an efficient sulfur host to construct high-capacity and high-energy density Li–S batteries with lean electrolytes . Two-dimensional heterogeneous composites formed by homogeneous grafting of mesoporous carbon on MXene nanosheets can not only accelerate the diffusion of Li + but also effectively improve the electrochemical conversion efficiency …”

“…19 Twodimensional heterogeneous composites formed by homogeneous grafting of mesoporous carbon on MXene nanosheets can not only accelerate the diffusion of Li + but also effectively improve the electrochemical conversion efficiency. 20 In this work, Co 1−x S/3D-Ti 3 C 2 T x composites with threedimensional(3D) multilayered structures were prepared by constructing hollow Ti 3 C 2 T x microspheres coupled with Co 1−x S nanoparticles. The Ti 3 C 2 T x microspheres are effectively prevented from restacking through the uniform anchoring of Co 1−x S nanoparticles via C−S bonds.…”