High-performance lithium–sulfur batteries using hierarchical Fe2O3/Ketjen black composites as sulfur host materials

The polysulfide shuttle effect limits the wide application of lithium–sulfur batteries, which have high energy density and specific capacity. In this work, hierarchical Fe2O3/Ketjen black (HFO/KB) composites are developed to improve the cycle performance of Li–S batteries. The HFO/KB hosts exhibit strong chemical adsorption toward polysulfide, which can effectively suppress the lithium polysulfide shuttle effect and further improve the utilization of active sulfur. As a result, lithium–sulfur batteries with Fe2O3/Ketjen black@S (HFO/KB@S) cathode deliver an initial discharge capacity of 1356 mAh/g and retain a high capacity of 1021 mAh/g after 100 cycles at 0.2 C. At the high rate of 2 C, the HFO/KB@S cathode exhibits a high capacity of 761 mAh/g after 500 cycles. This work demonstrates that the HFO/KB@S composites are promising cathode for future commercial applications of lithium–sulfur batteries.