Design a Catalytic Cathode Material with Abundant Oxygen Vacancies to Accelerate the Kinetics of Lean‐Electrolyte Lithium‐Sulfur Batteries

Abstract Lean‐electrolyte lithium‐sulfur (Li−S) batteries are confronted with sluggish reaction kinetics, which required high catalytic materials to improve electrochemical performance. Herein, high catalytic‐activity Ce‐doped TiO 2 nanoparticles were combined into reduced graphene oxides (rGO) as the sulfur cathode (Ce‐doped TiO 2 /rGO/S). The impact of doping amounts of Ce on oxygen vacancies (OVs) was studied. Among the different Ce doping amounts, the 0.4 wt% Ce doping TiO 2 (0.4 Ce−TiO 2 ) exhibits the best catalysis and adsorption for Li 2 S 6 due to the most OVs in 0.4 Ce−TiO 2 . Rich OVs can provide more active sites for sulfur adsorption and present stronger catalytic activity to polysulfides. With an electrolyte to sulfur (E/S) ratio of 7 μL mg S −1 , the 0.4 Ce−TiO 2 /rGO/S exhibits the best electrochemical capability when compared with TiO 2 /rGO/S and rGO/S. It has a high capacity of 1421.9 mAh g −1 at 0.1 C (1 C=1675 mA g −1 ), and excellent rate performance. The 0.4 Ce−TiO 2 /rGO/S also has a higher capacity and more stable cyclic performance than TiO 2 /rGO/S when the temperature elevates to 60 °C.