Interconnected Microporous and Mesoporous Carbon Derived from Pitch for Lithium–Sulfur Batteries

Abstract

Lithium–sulfur (Li–S) batteries receive great attention due to their high theoretical energy density and low cost. However, the sulfur–carbon cathode suffers from the polysulfide dissolution during cycling, and the severe shuttle effect limits the practical application of Li–S batteries. In this work, a carbon material (XU76 carbon) derived from industry-residual petroleum was synthesized with a simple and low-cost method. Nitrogen adsorption, small-angle neutron scattering (SANS), adsorption kinetics, and UV–vis spectroscopy results show that the interconnected micromesopores in XU76 could act as a reservoir and trap polysulfide intermediates efficiently. The XU76 carbon with high surface area (∼1005 m2 g–1), good electric conductivity, good ion transport, and optimized distribution of interconnected micromesopores is used as the sulfur host for trapping polysulfide intermediates and advancing sulfur redox kinetics. The Li–S battery with the sulfur–XU76 carbon cathode gives an initial discharge capacity of ∼1200 mAh g–1 in the initial cycle and reversible capacity of ∼700 mAh g–1 after 100 cycles at a C rate of 0.1 C while the Li–S battery with the sulfur–KB carbon cathode only delivers a discharge capacity of 400 mAh g–1 after 100 cycles. Also, a discharge capacity of 462 mAh g–1 is obtained after 200 cycles at a high C rate (1 C). The detailed reaction mechanism of sulfur–carbon cathodes is systematically studied at high C rates using operando Raman and S K-edge X-ray absorption spectroscopy.

Oxygen-Incorporated Lithium-Rich Iron Sulfide Cathodes for Li-Ion Batteries with Boosted Material Stability and Electrochemical Performance

“…S K -edge XANES spectra were recorded on the same set of samples (Figure b–d). To study the oxidation state of S and the degree of covalency of the Fe–S bond in sulfide materials like FeS and FeS 2 , metalloproteins S K -edge XAS have been extensively used. , The S K -edge spectra of both materials show a pre-edge feature, which is associated with the Li 2 S (charged terminal sulfur) , and covalently bound S to a transition metal. For comparison, FeS (S K-edge) and Li 2 S (S K-edge) spectra were also collected (Figure S9 b).…”

Soft carbon in non-aqueous rechargeable batteries: a review of its synthesis, carbonization mechanism, characterization, and multifarious applications

“…Ko et al fabricated a porous carbon using petroleum pitch precursors via a template carbonization that balanced all the desired properties. 80 The synthesized soft carbon (named as XU76) possessed a particle dimension, surface area, mesopore size, and pore volume of 20 nm, 1005 m 2 g −1 , 4.0 nm, and 0.6 m 2 g −1 , respectively, enabling 66% sulfur loading, while for the vapor-phase aggregated commercial Ketjen Black (KB) carbon, the values were 50 nm, 1205 m 2 g −1 , 3.9 nm, and 1.7 m 2 g −1 , respectively, realizing only 55% sulfur loading. The mesopore-dominant (as revealed by small-angle neutron scattering) KB carbon delivered only 400 mA h g −1 after 100 cycles at a C/10 rate, whereas XU76 having an interconnected pore geometry demonstrated a value of ∼700 mA h g −1 after 100 cycles under similar cycling conditions (Fig.…”

Designing polysulfides adsorption‐conversion on g‐C3N4‐based separator via doping heteroatoms boron and phosphorus toward high‐performance lithium‐sulfur batteries

“…[6][7][8][9][10] Addressing the "shuttle effect" has been the focus of significant research efforts. [11][12][13][14][15][16] Incorporating sulfur into the polar cathode host, such as doped carbon materials, [17][18][19] metal oxides, [20][21][22][23][24][25][26] metal sulfides, [27][28][29][30][31][32][33] conductive polymers, [34][35][36][37] and metal-organic frameworks (MOFs) 26,[38][39][40][41][42] to facilitate the storage and conversion of LiPSs is efficient in restraining the shuttling action. However, the introduction of multitudinous inactive substances impairs the integral energy density.…”