Approaching Ultrastable High‐Rate Li–S Batteries through Hierarchically Porous Titanium Nitride Synthesized by Multiscale Phase Separation

Abstract

Porous architectures are important in determining the performance of lithium–sulfur batteries (LSBs). Among them, multiscale porous architecutures are highly desired to tackle the limitations of single‐sized porous architectures, and to combine the advantages of different pore scales. Although a few carbonaceous materials with multiscale porosity are employed in LSBs, their nonpolar surface properties cause the severe dissolution of lithium polysulfides (LiPSs). In this context, multiscale porous structure design of noncarbonaceous materials is highly required, but has not been exploited in LSBs yet because of the absence of a facile method to control the multiscale porous inorganic materials. Here, a hierarchically porous titanium nitride (h‐TiN) is reported as a multifunctional sulfur host, integrating the advantages of multiscale porous architectures with intrinsic surface properties of TiN to achieve high‐rate and long‐life LSBs. The macropores accommodate the high amount of sulfur, facilitate the electrolyte penetration and transportation of Li+ ions, while the mesopores effectively prevent the LiPS dissolution. TiN strongly adsorbs LiPS, mitigates the shuttle effect, and promotes the redox kinetics. Therefore, h‐TiN/S shows a reversible capacity of 557 mA h g−1 even after 1000 cycles at 5 C rate with only 0.016% of capacity decay per cycle.

A Comprehensive Review of Materials with Catalytic Effects in Li–S Batteries: Enhanced Redox Kinetics

“…d) Galvanostatic test of ordered mesoporous carbon (OMC), h‐TiN, and m‐TiN electrodes at 0.5 C. Reproduced with permission from ref. . Copyright 2018 Wiley‐VCH.…”

Expediting redox kinetics of sulfur species by atomic‐scale electrocatalysts in lithium–sulfur batteries

“…[17][18][19][20][21][22][23] This strategy is recently coupled with precise surface modification, endowing electrode substrates or functional separators with lithiophilicity and sulfiphilicity to kinetically promote S/Li 2 S precipitation and regulate LiPS transport. [24][25][26][27][28] Directly blending metal oxides, [29][30][31][32][33] sulfides, [34][35][36] nitrides, [37][38][39] and carbide 40,41 with various carbonaceous hosts has demonstrated considerable merits to mediate sulfur species' behaviors through chemisorption and/or electrocatalysis mechanisms. [42][43][44][45][46] Nevertheless, the low surface-to-volume ratio of these additives cannot entirely bring active sites to the reaction surface.…”

Dense MoS2 Micro‐Flowers Planting on Biomass‐Derived Carbon Fiber Network for Multifunctional Sulfur Cathodes

“…In addition, as the scan rates increase, the S-MoS 2 /CFs electrode displays a less decrease in onset potentials for peaks I, II, and III ( Figure. 6a, b) than S-CFs (Figure 6c, d), demonstrating the accelerated redox conversion of LPSs on MoS 2 /CFs. [22,38] The electrocatalytic effect was also analyzed by Tafel slope using the CV curve at 0.1 mV s À 1 . S-MoS 2 /CFs displays Tafel slope of 78 mV dec À 1 (Figure 6e), much smaller than that of S-CFs (198 mV dec À 1 ) (Figure 6f), suggesting the enhanced redox kinetics of LPSs over S-MoS 2 /CFs.…”

“…To further enhance the binding with LPSs, the third category, namely, polar and conductive transition metal compounds collaborated with carbon materials, such as transitional metal oxides, [18,19] carbides, [20] nitrides, [21][22][23] sulfides [24][25][26][27] and porphyrin, [28] have emerged to chemically adsorb LPSs. Generally, most of the previously reported transition metal composites are either micro-sized or bulk materials, restricting available anchoring sites towards LPSs.…”