Dodecylamine‐Induced Synthesis of a Nitrogen‐Doped Carbon Comb for Advanced Lithium–Sulfur Battery Cathodes

Abstract

cycling life, significant self-discharge, and decreased Coulombic efficiency of the batteries. [3][4][5] The second is the inherent poor electrical conductivity of the sulfur that often results in unsatisfactory rate capabilities and the poor utilization of sulfur. [6][7][8] To tackle the first issue, tremendous efforts have been made to develop a facile approach to realize the physical confinement of soluble sulfur species within the pores of nonpolar hydrophobic carbon materials, such as highly ordered mesoporous carbons, [9][10][11][12] hollow carbon spheres (HCSs), [8,[13][14][15][16] carbon papers, and graphene foams. [17,18] Typically, the physisorption capability is determined by capillary force, which is created as a result of the porous structure of the materials. [19,20] Therefore, the design of electrode architectures with unique pore structures (micro-, meso-, and macroporous) is one of the most important directions toward the development of a carbon-based host for Li-S batteries. In our previous work, the excellent confinement of polysulfides was achieved by utilizing HCSs with unique indented-void shells. [16] In our most recent work, a stable cycling performance at a high rate was also achieved by the rational design of HCSs with highly ordered mesoporous shells. [21,22] However, the performance, particularly the cycle stability, of Li-S cathodes is still insufficient based simply on physisorption because the weak adsorption capability of nonpolar hydrophobic carbon hosts for the highly polar hydrophilic Li 2 S x (4 ≤ x ≤ 8) is far from satisfactory. [23] Therefore, further improvement is still required.Anchoring the soluble Li 2 S x species via chemisorption using heteroatom-doped carbon, [24,25] graphitic carbon nitride (e.g., C 3 N 4[26-28] ), oxides (e.g., MnO 2 , [29,30] TiO 2 , [31] Ti 4 O 7 , [32] CeO 2 [33] ), nitrides (e.g., VN, [34] TiN [35] ), and sulfides (Co 9 S 8 , [36] NiS, [37] TiS 2 [38] ) have been extensively exploited and results in higher efficiency toward suppressing the sulfur loss than physical confinement. However, some of these materials have a poor electrical conductivity, requiring a large number of conductive additives to receive a decent rate performance. [28,30] N-doped carbon is considered a promising host material for sulfur due to the Lewis acid-base interaction between Li ions in the polysulfides and N atoms in the carbon matrix, thus contributing to effective suppression of polysulfide shuttling during charging. [39][40][41][42] Additionally, nitrogen doping can increase the intrinsic electrical conductivity of carbon materials, which enhances the rate performance.Host materials that can provide both a strong absorbability of soluble intermediate polysulfides and a high electronic conductivity are in high demand to realize practical applications of Li-S batteries. Here, the rational design of an N-doped carbon comb (NCC) as a new type of sulfur host for Li-S batteries, delivering a favorable performance, particularly a good cycling stability and rate capability, ...

Direct growth of ordered N‐doped carbon nanotube arrays on carbon fiber cloth as a free‐standing and binder‐free air electrode for flexible quasi‐solid‐state rechargeable Zn‐Air batteries

“…As shown in Figure S1E, the sharp nitrogen uptake at a low relative pressure region (p/p 0 < 0.1) and the obvious hysteresis at a moderate relative pressure region (p/ p 0 > 0.45) implies the existence of micropore and mesopore, respectively. 31,32 The pore size distribution of CC-A was calculated by Barrett-Joyner-Halenda equation from adsorption curve, showing the overall pore size of smaller than 10 nm and average pore size of about 2.2 nm ( Figure S1F). The pore volume was calculated to be 0.13 cm 3 /g.…”

“…From the high-resolution C 1s XPS spectrum in Figure 2C, five peaks with bond energies of 284.6, 285.6, 286.5, 288.2, and 291.4 eV are observed, which can be identified to the C-C, C-N/C-O, C═N/C═O, O═C-O, and π-π*, respectively. 31,35 The presence of C and N bonds in XPS demonstrated nitrogen was successfully incorporated into the structure of carbon nanotubes during the growth of carbon nanotubes via chemical vapor deposition. It was suggested that the ORR activity of carbon materials is greatly affected by the configuration of the C and N bonds in their structure.…”

“…The O 1s spectrum can be deconvoluted into five peaks located at 529.9, 531.4, 532.7, 534.3, and 536.4 eV, which are assigned to Co-O, C═O, C-O, O═C-O, and H 2 O*, respectively. 25,31,41 In addition, the atomic and mass contents of C, N, O, and Co were listed in Table S1. It was demonstrated that the surface oxygen-contained groups are highly active for ORR and OER.…”

Host Materials Anchoring Polysulfides in Li–S Batteries Reviewed

“…Lu et al designed a new dodecylamine micelle-induced nitrogen-doped carbon comb (NCC) as sulfur host. [154] This nitrogen-doped NCC substantially increased the conductivity of cathodes and introduced the chemical anchoring toward polysulfides, effectively suppressing the losses of sulfur species upon cycling. As a result, NCC with a high loading of sulfur achieved an impressive cycling lifespan and rate performance.…”

Simplifying the synthesis of carbon inverse opals

“…[16][17][18][19][20][21][22][23] Previous reports on the synthesis of carbon IOs have detailed the use of complex precursors, which oen require convoluted processing procedures. These include, HF etching to remove the template material, 24,25 chemical vapor deposition for template inlling, 26 and the use of toxic carbon-precursors, including a phenol-formaldehyde resorcinol, a mixture of furfuryl alcohol and oxalic acid, and bis-ortho-diynyl arsene (BODA) monomers. [27][28][29][30][31] The aim of this study is to simplify the synthesis procedure for carbon IOs.…”