Synergistic effect of titanium‐oxide integrated with graphitic nitride hybrid for enhanced electrochemical performance in lithium‐sulfur batteries

Abstract

Lithium-sulfur (Li-S) secondary batteries have been limited by the poor cyclic stability, mainly caused by the dissolution polysulfide species into the electrolyte and subsequent irreversible shuttling effect. Recently, addition of the polysulfide adsorbents within sulfur cathode is effectively improving the electrochemical performance. Herein, TiO 2 integrated with g-C 3 N 4 (TiO 2 @g-C 3 N 4 : TOCN) hybrid was prepared by a facile heating treatment from the precursor of urea and TiO 2 composites, which used as host material for elemental sulfur (TOCN@S) in Li-S batteries. The multifunctional TOCN not only reduced the electrochemical resistance but also provided strong adsorption sites to immobilize sulfur and polysulfide. As a result, the TOCN@S cathode with a sulfur content of 74.5 wt% and a sulfur loading of 3.1 mg cm −2 exhibits a high initial capability of 804 mAh g −1 at 0.5 C with capacity retention of 67.2% after 500 cycles. Additionally, the composite cathode also possesses excellent high-rate performance, retaining a remarkable specific capacity of 630 mAh g −1 even at a rate of 2 C.

CoS2-Decorated Cobalt/Nitrogen Co-Doped Carbon Nanofiber Networks as Dual Functional Electrocatalysts for Enhancing Electrochemical Redox Kinetics in Lithium–Sulfur Batteries

“…The profiles show two discharge plateaus Q a and Q b , respectively. The ratio of Q b /Q a reflects the kinetic conversion of polysulfides. , The CSCNC@Li 2 S 6 electrode has a higher Q b /Q a (2.45) than that of the CNC@Li 2 S 6 electrode (2.11), which indicates that CSCNC can boost utilization and accelerate conversion of polysulfides. The peak current for the potentiostatic polarization curves is shown in Figure (c).…”

Nanoscale CuFe2O4 Uniformly Decorated on Nitrogen‐Doped Carbon Nanofibers as Highly Efficient Catalysts for Polysulfide Conversion in Lithium‐Sulfur Batteries

“…Hence, a series of heteroatoms doping with N, O and B atoms can provide strong chemical interaction and good electrical conductivity, which can form plenty of active sites and further restrict polysulfides upon the surface of carbon materials [13,14] . Meanwhile, various kinds of polar compounds including metal oxides (MoO 2 , [15] TiO 2 , [16] La 2 O 3 [17] ), sulfides (MoS 2 , [18] SnS 2 , [19] CoS 2 [20] ), carbides (Ti 3 C 2 , [21] Fe 3 C, [22] Mo 2 C [23] ) have been investigated as more effective immobilizers and convertors of polysulfides owing to the strong chemical adsorption capability and dominant catalytic ability towards polysulfides.…”

High‐performance nanostructure Fe 2 O 3 synthesized via novel direct current electric arc method as sulfur‐wrapping matrix for lithium‐sulfur batteries

“…To solve these problems, many researchers propose developing high-performance matrix materials to immobilize sulfur onto its surface via physical and chemical adsorption, so as to inhibit the shuttle effect of polysulfide and improve the sulfur conductivity. [5][6][7][8][9] Right now, the main types of matrix materials include carbon, inorganic metal compounds, conductive polymers, etc. [10][11][12][13] Carbon materials due to their stable structure, abundant pore structure and high conductivity are taken the lead in applying to the sulfurwrapping matrix material for many years.…”

“…However, the practicability has been seriously affected because of sulfur insulativity, volumetric expansion and “shuttle effect” caused by the solution of polysulfides (Li 2 S n [n = 4‐8]) during the electrochemical process, which results in low actual specific capacity and rapid capacity loss. To solve these problems, many researchers propose developing high‐performance matrix materials to immobilize sulfur onto its surface via physical and chemical adsorption, so as to inhibit the shuttle effect of polysulfide and improve the sulfur conductivity 5‐9 . Right now, the main types of matrix materials include carbon, inorganic metal compounds, conductive polymers, etc 10‐13 .…”