Synergistic realization of Co/N co-doped hierarchical vanadium trioxide core–shell sphere for ultra-long cycle performance of Li–S batteries

Lithium–sulfur (Li–S) battery has been recognized as one of the most promising energy systems due to its high specific capacity and energy density. However, its instinct defects, such as shuttle effect of lithium polysulfide (LPS), low conductivity, and high volume expansion of cathode sulfur (S), seriously hinder its commercialization process. Herein, a hierarchical vanadium trioxide (V2O3) core–shell sphere, which is self-assembled from zero-dimensional (0D) nanoparticles and integrated with 2D nanosheets and co-doped cobalt (Co) and nitrogen (N), has been prepared. After the hierarchical V2O3 core–shell sphere being served as a separator modifier, a synergistic effect of physisorption, chemisorption, and catalytic conversion of LPS can be well realized, leading to an effective inhibition of the shuttle effect. Hence, exceptional initial discharging capacities of 1485.3 and 1322.2 mAh g−1 can be obtained at 0.1 and 1C, respectively, and after 1100 ultra-long cycles, the capacity loss rate can be restricted at 0.064% per cycle; furthermore, a discharging capacity of 973.9 mAh g−1 can also be obtained even at a high current of 3C, and the capacity loss rate is only 0.059% per cycle during 1000 ultra-long cycles, showing extraordinary ultra-long cycle performance and rate performance.