Covalent Encapsulation of Sulfur in a MOF‐Derived S, N‐Doped Porous Carbon Host Realized via the Vapor‐Infiltration Method Results in Enhanced Sodium–Sulfur Battery Performance

Abstract

Practical applications of room temperature sodium–sulfur batteries are still inhibited by the poor conductivity and slow reaction kinetics of sulfur, and dissolution of intermediate polysulfides in the commonly used electrolytes. To address these issues, starting from a novel 3D Zn‐based metal–organic framework with 2,5‐thiophenedicarboxylic acid and 1,4‐bis(pyrid‐4‐yl) benzene as ligands, a S, N‐doped porous carbon host with 3D tubular holes for sulfur storage is fabricated. In contrast to the commonly used melt‐diffusion method to confine sulfur physically, a vapor‐infiltration method is utilized to achieve sulfur/carbon composite with covalent bonds, which can join electrochemical reaction without low voltage activation. A polydopamine derived N‐doped carbon layer is further coated on the composite to confine the high‐temperature‐induced gas‐phase sulfur inside the host. S and N dopants increase the polarity of the carbon host to restrict diffusion of sulfur, and its 3D porous structure provides a large storage area for sulfur. As a result, the obtained composite shows outstanding electrochemical performance with 467 mAh g−1 (1262 mAh g−1(sulfur)) at 0.1 A g−1, 270 mAh g−1 (730 mAh g−1(sulfur)) after 1000 cycles at 1 A g−1 and 201 mAh g−1 (543 mAh g−1(sulfur)) at 5.0 A g−1.

Metal–organic framework-based materials: advances, exploits, and challenges in promoting post Li-ion battery technologies

“…MOF-derived carbon is very effective as a sulfur host for MS batteries. 57 Conventional porous carbon materials that are used as sulfur host MOFs bind to sulfur passively. Thus, the grip of carbon materials on sulfur is not very good, leading to less sulfur loading and also the dissolution of sulfur.…”

Recent Advances in Emerging Non‐Lithium Metal–Sulfur Batteries: A Review

“…[66] Porous Carbon Material-Based Sulfur Hosts: Porous carbon architectures with large specific surface areas and abundant pores are promising hosts for Na-S batteries. [67][68][69][70][71][72] The large specific surface area and high pore volume not only ensure a high sulfur content in the composite cathodes but also alleviate the volume changes of sulfur. In addition, the high electrical Figure 3.…”

“…Rogach et al reported a MOF-derived S, N co-doped porous carbon skeleton with 3D tubular holes for Na-S batteries (Figure 5a). [72] Using a vapor-infiltration method, sulfur species were bonded with the carbon structures; this method is different from the commonly employed melt-diffusion method to physically confine sulfur species. The sulfur cathodes demonstrated outstanding electrochemical performance with high capacities (467 mAh g −1 at 0.1 A g −1 , 270 mAh g −1 after 1000 cycles at 1.0 A g −1 ) and excellent rate capability (304 mAh g −1 at 10 A g −1 ).…”

“…Ex situ Raman spectroscopy has also been employed to probe phase transformation in non-lithium MSBs. [31,72,83,84,154,155] Ex situ Raman spectra of Na-S batteries were collected during the first two discharge and charge processes, as shown in Figure 16b. [72] The presence of the C-S peak and the disappearance of the S-S peak implied the conversion of S 8 molecules into Na 2 S, which was confirmed by other studies that used covalent polymer-sulfur cathodes.…”

Defect Engineering for Expediting Li–S Chemistry: Strategies, Mechanisms, and Perspectives

“…For another, Li 2 S is prone to accumulating at the cathode side, which is not easy to be efficiently dissociated.Recent years have witnessed a burgeoning interest in designing adsorptive and electrocatalytic mediators for effective PS management in Li-S realm, in order to essentially expedite redox kinetics and inhibit "shuttle effect." [14][15][16][17][18][19][20] Although strenuous efforts have been devoted to exploring various types of PS mediators including carbonaceous materials, [21][22][23][24][25] metal oxides/carbides/nitrides/borides/ sulfides/selenides/phosphides, [26][27][28][29][30][31][32][33][34][35][36] and heterostructures, [37][38][39][40][41][42][43][44] their unsatisfactory adsorptive and catalytic behavior caused by insufficient active sites remains a huge barrier for obtaining favorable Li-S chemistry. To circumvent this problem, adjusting the morphology of PS mediators such as reducing their size to nanoscale has been recognized as a promising method to expose more active lattice planes and edge sites.…”