Single-atomic tungsten-doped Co3O4 nanosheets for enhanced electrochemical kinetics in lithium-sulfur batteries

The practical application of lithium-sulfur batteries (LSBs) is severely hindered by the undesirable shuttling of lithium polysulfides (LiPSs) and sluggish redox kinetics of sulfur species. Herein, a series of ultrathin single-atomic tungsten-doped Co3O4 (W-x-Co3O4) nanosheets as catalytic additives in the sulfur cathode for LSBs are rationally designed and synthesized. Benefiting from the enhanced catalytic activity and optimized electronic structure by W doping, the W-x-Co3O4 not only reduces the shuttling of LiPSs but also decreases the energy barrier of sulfur redox reactions of sulfur species, leading to accelerated electrode kinetic. As a result, LSB cathodes with the use of 5.0 wt% W-0.02-Co3O4 as the electrocatalyst show the high reversible capacities of 1217.0 and 558.6 mAh g(-1) at 0.2 and 5.0 C, respectively, and maintain a high reversible capacity of 644.6 mAh g(-1) at 1.0 C (1.0 C = 1675 mA g(-1)) after 500 cycles. With a high sulfur loading of 5.5 mg cm(-2) and electrolyte-electrode ratio of 8 mu L-electrolyte mg(sulfur)(-1), the 5.0 wt% W-0.02-Co3O4-based sulfur cathode also retains a high reversible areal capacity of 3.86 mAh cm(-2) at 0.1 C after 50 cycles with an initial capacity retention of 84.7%.