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 V2O5 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 V2O5, and enriches the oxygen vacancy defects. Thus, the doped V2O5 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-V2O5 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-V2O5 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.