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

Abstract

AbstractLean‐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 TiO2 nanoparticles were combined into reduced graphene oxides (rGO) as the sulfur cathode (Ce‐doped TiO2/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 TiO2 (0.4 Ce−TiO2) exhibits the best catalysis and adsorption for Li2S6 due to the most OVs in 0.4 Ce−TiO2. 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 mgS−1, the 0.4 Ce−TiO2/rGO/S exhibits the best electrochemical capability when compared with TiO2/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−TiO2/rGO/S also has a higher capacity and more stable cyclic performance than TiO2/rGO/S when the temperature elevates to 60 °C.