Engineering a TiNb₂O₇-Based Electrocatalyst on a Flexible Self-Supporting Sulfur Cathode for Promoting Li-S Battery Performance

Abstract

Lithium-sulfur (Li-S) batteries are considered a prospective energy storage system because of their high theoretical specific capacity and high energy density, whereas Li-S batteries still face many serious challenges on the road to commercialization, including the shuttle effect of lithium polysulfides (LiPSs), their insulating nature, the volume change of the active materials during the charge−discharge process, and the tardy sulfur redox kinetics. In this work, double transition metal oxide TiNb 2 O 7 (TNO) nanometer particles are tactfully deposited on the surface of an activated carbon cloth (ACC), activating the surface through a hydrothermal reaction and high-temperature calcination and finally forming the flexible self-supporting architecture as an effective catalyst for sulfur conversion reaction. It has been found that ACC@TNO possesses many catalytic activity sites, which can inhibit the shuttle effect of LiPSs and increase the Coulombic efficiency by boosting the redox reaction kinetics of LiPS transformation reaction. As a consequence, the ACC@TNO/S cathode exhibits an impressive electrochemical performance, including a high initial discharge capacity of 885 mAh g −1 at a high rate of 1 C, a high discharge specific capacity of 825 mAh g −1 after 200 cycles with a prominent capacity retention rate of 93%, and a small decay rate of 0.034% per cycle. Although TNO is extensively used in the fields of lithium ion batteries and other rechargeable batteries, it is first introduced as sulfur host materials to boost the redox reaction kinetics of the LiPS transformation reaction and increase the electrochemical performance of Li-S batteries. Therefore, studies of the synergistic effect on the chemical absorption and catalytic conversion effect of TNO for LiPSs of Li-S batteries provide a good strategy for boosting further the comprehensive electrochemical performances of Li-S batteries.

d-p Hybridization-Induced “Trapping–Coupling–Conversion” Enables High-Efficiency Nb Single-Atom Catalysis for Li–S Batteries

“…Another significant indication of Li–S performance with S@Nb–SAs@NC electrode is the rate capability. The battery using S@Nb–SAs@NC electrode achieves high discharge capacities of 1200, 1115, 1033, 983, 907, 806, and 740 mA h g –1 at the rates of 0.2, 0.5, 1, 2, 3, 5, and 7 C, respectively, which surpass those of S@NC, S@C (Figure b), and a majority of reported M-SAs and Nb-based cathodes (Figure c). − Also, a high capacity of 1091 mA h g –1 is recovered after switching back to 0.5 C, revealing high kinetic reversibility of the cell employed S@Nb–SAs@NC cathode. To reveal the merit of the S@Nb–SAs@NC cathode, the prolonged cycling stability is further evaluated at 2 C (Figure S25) and 4 C (Figure d).…”

Combined physical confinement and chemical adsorption on co-doped hollow TiO2 for long-term cycle lithium–sulfur batteries

“…3c), deconvolution fitted three peaks located at 458.5 eV, 459.7 eV, and 460.6 eV, which may be ascribed to the Ti–S, Ti–O, and Ti–N binding energy, respectively. 13 The fitted curves of Ti–S and Ti–N bonds in the S@DHT sample indicates that elemental sulfur and nitrogen were doped during the thermal treatment process. This conclusion is further verified using the high-resolution XPS fitting curves of the S 2p and N 1s electrons; two peaks of the curve located at 162.2 eV and 396.8 eV may be ascribed to the S–Ti and N–Ti binding energy, respectively 14 (Fig.…”

Catalytic Effects of Electrodes and Electrolytes in Metal–Sulfur Batteries: Progress and Prospective

“…Ni-N 5 /HNPC/S 1188 mAh g -1 at 0.2 C 684 mAh g -1 at 4 C 1 m LiTFSI in DOL/DME with 0.1 m LiNO 3 [13] Fe-N-C Mesocellular carbon foam Fe-N-C/S-MCF 1244 mAh g -1 at 0.1 C 798 mAh g -1 at 5 C 1 m LiTFSI in DOL/DME with 2% LiNO 3 [14] Co 4 W 18 Clusters Co 4 W 18 /rGO 1426 mAh g -1 at 0.05 C 644 mAh g -1 at 5 C 0.5 m LiTFSI and 0.5 m LiNO 3 in DOL/ DME [15] P-doped NiTe 2 Nanosheet MSC/P⊂NiTe 2− 1318 mAh g -1 at 0.2 C 764 mAh g -1 at 5 C 1 m LiTFSI in DOL/DME [16] Fe 2 O 3 /N-MC Hierarchical structure S@Fe 2 O 3 /N-MC, 1172 mAh g -1 at 0.2 C 740 mA h g -1 at 5 C 1 m LiTFSI in DOL/DME with 1% LiNO 3 [17] Co 9 S 8 /Co Nanoparticle Li 2 S-Co 9 S 8 /Co 1006 mAh g -1 at 0.1 C 616 mAh g -1 at 4 C 1 m LiTFSI and 0.2 m LiNO 3 in tetraglyme [18] Ti 3 C 2 MXene Nanosheet S/3D e-Ti 3 C 2 -2 1205.9 mAh g -1 at 0.2 C 772.4 mAh g -1 at 5.0 C 1 m LiTFSI in DOL/DME with 1% LiNO 3 [19] MoS 2 Monolayer MoS 2 -500 532 mAh g -1 at 5.0 C 1 m LiTFSI in DOL/DME with 2% LiNO 3 [20] Halloysite TiO 2 Nanoparticle SC-TiO 2 -Hal/S 1037.6 mAh g -1 at 0.2 C 566.9 mAh g -1 at 5.0 C 1 m LiTFSI in DOL/DME with 0.1 m LiNO 3 [21] TiC Nanoparticle TiC@CNF/S 1058 mAh g -1 at 0.2 C 738 mAh g -1 at 5.0 C 1 m LiTFSI in DOL/DME with 2% LiNO 3 [22] NiO-Ni 3 N Nanoparticle NiO-Ni 3 N-AC-S 1179 mAh g -1 at 0.2 C 652 mAh g -1 at 4.0 C 1 m LiTFSI in DOL/DME with 1% LiNO 3 [23] Borophene sheets CNT/B 1329 mAh g -1 at 0.2 C 919 mAh g -1 at 4.0 C 1 m LiTFSI in DOL/DME with 1% LiNO 3 [24] TiNb 2 O 7 Nanoparticle ACC@TNO 1399 mAh g -1 at 0.1 C 885 mAh g -1 at 4.0 C 1 m LiTFSI in DOL/DME with LiNO 3 [25] In 2 S 3−x Marigold-like Nanoparticle…”