Strain Engineering of a MXene/CNT Hierarchical Porous Hollow Microsphere Electrocatalyst for a High‐Efficiency Lithium Polysulfide Conversion Process

Abstract

Tensile-strained Mxene/carbon nanotube (CNT) porous microspheres were developed as an electrocatalyst for the lithium polysulfide (LiPS) redoxr eaction. The internal stress on the surface results in lattice distortion with expanding TiÀTi bonds,e ndowing the Mxene nanosheet with abundant active sites and regulating the d-band center of Ti atoms upshifted closer to the Fermi level, leading to strengthened LiPS adsorbability and accelerated catalytic conversion. The macroporous framework offers uniformed sulfur distribution, potent sulfur immobilization, and large surface area. The composite interwoven by CNT tentacle enhances conductivity and prevents the restacking of Mxene sheets.This combination of tensile strain effect and hierarchical architecture design results in smooth and favorable trapping-diffusion-conversion of LiPS on the interface.T he Li-S battery exhibits an initial capacity of 1451 mAh g À1 at 0.2 C, rate capability up to 8C,and prolonged cycle life.

Self‐Assembly of 0D–2D Heterostructure Electrocatalyst from MOF and MXene for Boosted Lithium Polysulfide Conversion Reaction

“…[ 31,32 ] Recently, Chen and co‐workers proposed a MX/CNT hierarchical porous hollow microsphere electrocatalyst that effectively immobilized and accelerated polysulfide conversion. [ 33 ] This MX/CNT sulfur cathode maintained superb rate performance up to 8 C and good cyclic stability with a low capacity decay of 0.08% cycle −1 . To date, however, there have been very few reports on the use of MOF‐derived selenides on nitrogen‐doped MX nanosheets to fabricate 0D–2D heterostructure sulfur electrocatalysts.…”

Unraveling the Catalytic Activity of Fe–Based Compounds toward Li2Sx in Li–S Chemical System from d–p Bands

“…Recently, the researchers have demonstrated that configuring the interlayer between the separator and sulfur cathode is an effective way to alleviate the "shuttle effect" in Li-S redox system. [38][39][40][41][42] To avoid the heavy and large volume of the free-standing interlayer, people have begun to modify the separator with functional materials, such as structural carbon materials [43][44][45][46][47][48] and metal-based compounds. [49,50] As the typical earthabundant, low-cost, and environmentally friendly materials, iron-based compounds have already been widely researched in Li-S batteries.…”

Engineering Oversaturated Fe‐N5 Multifunctional Catalytic Sites for Durable Lithium‐Sulfur Batteries

“…[24] To further verify the catalytic role on the Fe-N 5 -C surface for LiPS conversion, symmetrical cells were constructed using Li 2 S 6 -containing electrolyte.A ss hown in Figure 4d,C V curves were recorded with ar ange of voltage from À1.5 to 1.5 Vw ith different electrodes.T he Fe-N 5 -C electrode exhibits distinct redox peaks at À0.24/0.24 eV and À0.45/ 0.45 eV with the highest current response compared with that of the N-C and Fe-N 4 -C electrodes,c onfirming superior electro-catalytic activity towards efficient LiPS conversion. [25] As shown in Figure 4e,the CV profiles in the first three cycles perform ah igh coincidence,s uggesting the excellent conversion stability on the Fe-N 5 -C.A part from that, the CV curves of N-C and Fe-N 4 -C are shown in Figure S8, blunt peaks can be observed, demonstrating the slow kinetics. Moreover,t he different scan rates CV curves of symmetric cells were also analyzed in Figure S9.…”