Defect-Rich W/Mo-Doped V₂O₅ Microspheres as a Catalytic Host To Boost Sulfur Redox Kinetics for Lithium–Sulfur Batteries

Abstract

It is very important to develop ideal electrocatalysts to accelerate the sulfur redox kinetics in both the discharging and charging processes for high-performance lithium−sulfur batteries. Herein, defect-rich cation-doped V 2 O 5 yolk−shell microspheres are reported as a catalytic host of sulfur. The doping of W or Mo cations induces no impurities, broadens the lattice spacing of V 2 O 5 , and enriches the oxygen vacancy defects. Thus, the doped V 2 O 5 host affords sufficient active sites for chemically anchoring polysulfides and promising catalytic effect on the mutual conversion between different sulfur intermediates. As a result, the S/W−V 2 O 5 cathode delivers a discharging capacity of 1143.3 mA g −1 at an initial rate of 0.3 C and 681.8 mA g −1 at 5 C. Even under a sulfur loading of up to 5.5 mg cm −2 and a minimal electrolyte/sulfur ratio of 6 μL mg −1 , the S/W−V 2 O 5 cathode could still achieve good sulfur utilization and dependable cycle stability. Thus, this work offers an electrocatalytic host based on the cation doping strategy to greatly enhance the sulfur redox kinetics for high-performance Li−S batteries.

In Situ Construction of a LiF/LiCl-Rich Solid Electrolyte Interphase for Lithium Ion Unimpeded Transport

“…The increased F signal confirms our speculation. In the C 1s spectrum (Figure S8a,b), the two SEI films exhibit four intermediate binding states at 284.8, 286.6, 288.8, and 290.2 eV, corresponding to binding energies of C–C, C–H, COOR, and CO 3 2– , respectively. − Peaks corresponding to Li 2 O, C–O, CO 3 2– , and COOR were observed at binding energies of 530.9, 531.9, 533.3, and 533.9 eV, respectively, in the O 1s indication spectra in Figure S9a,b. , As shown in Figure S10, the peak of the S 2p spectrum is attributed to SO x 2– . − However, the peak at the binding energy of the Li 1s spectrum at 56.2 in the SEI layer, which contains the C 4 H 2 Cl 2 S additive, corresponds to LiCl/LiF (Figure a–d). This indicates that the SEI layer that is formed is rich in LiCl and LiF.…”

In Situ Encapsulation of Cobalt Selenide Nanoparticles in N-Doped Carbon Nanotubes with a Full Sulfiphilic Surface as a Catalytic Interlayer for Lithium–Sulfur Batteries

“…To solve the above problems, various designed materials such as porous carbons, − metal compounds, − or their combination − have been used as the interlayer at the cathode/separator interface, instead of the host of sulfur, and proven effective to reduce the shuttle effect of LiPSs. Such an integration of material design and configuration modification of sulfur cathodes is simple and feasible to achieve a remarkable improvement of sulfur utilization and cycle stability of LSBs. − The involved interlayers can not only effectively prevent the dissolved LiPSs from diffusing toward the Li anode side via both physical restriction and chemical confinement but also act as the second current collector for the electrochemical redox of the trapped LiPSs. − In addition, the polysulfide adsorption–catalysis ability of the designed catalytic materials plays a key role in regulating the redox reaction of LiPSs.…”

Bifunctional K3PW12O40/Graphene Oxide-Modified Separator for Inhibiting Polysulfide Diffusion and Stabilizing Lithium Anode

“…Lithium–sulfur (Li–S) batteries are considered as promising candidates for next-generation batteries due to their high theoretical energy density of 2600 Wh kg –1 and low cost of sulfur. − However, the practical application of Li–S batteries is hindered by several challenges. Specifically, the insulative nature of sulfur and the formation of nonconductive discharge products (Li 2 S 2 and Li 2 S) result in sluggish redox reaction kinetics. − Moreover, the “shuttle effect” of dissolved long-chain lithium polysulfide intermediates (Li 2 S n , 4 ≤ n ≤ 8) during the discharge/charge process leads to inferior Coulombic efficiency, abnormal capacity degradation, and the inevitable loss of active material. − To make matters worse, the growth of lithium dendrites arising from uneven Li + stripping/deposition brings a short cycle life and serious safety concerns. , …”