Engineering rare earth metal Ce-N coordination as catalyst for high redox kinetics in lithium-sulfur batteries

Abstract

Lithium-sulfur (Li-S) batteries are a key area of research in energy storage due to their high theoretical energy density, low cost, and environmental friendliness. However, the shuttle effect caused by lithium polysulfides (LiPSs) intermediates often results in poor cycling stability. Therefore, constructing rational cathode structures to achieve fast reaction kinetics in adsorbing and catalyzing LiPSs is the key to obtain high-performance Li-S batteries. Metallic single-atom catalysts (SACs), known for their 100 % atomic utilization rate and low cost, have demonstrated excellent catalytic activity and selectivity in the redox reactions of Li-S batteries, positioning them as one of the most promising catalysts in this field. Rare earth metallic SACs with versatile oxidation states, diverse coordination chemistry and environmentally friendly are rarely investigated in Li-S system. Herein, we fabricate a rare earth metal-based single-atom catalyst (CeSAs) supported on a three-dimensional porous N-doped carbon (3DCeSA-N-WS), and systematically study its performance in Li-S batteries. Benefitting from the atomic dispersion and versatile oxidation states (Ce³⁺/Ce⁴⁺), the 3DCeSA-N-WS demonstrates excellent performance in anchoring and catalyzing LiPSs, significantly enhancing the redox reaction kinetics. Consequently, the prepared sulfur cathode exhibits exceptional electrochemical performance, with a high initial specific discharge capacity of 1225 mAh g⁻¹ at 0.2 C and a capacity retention of 76.1 % after 160 cycles. The assembled 100 mAh-level pouch cellmaintains a high specific discharge capacity of 877 mAh g⁻¹ after 50 cycles at 0.5 C. This work provides new insights into the design of sulfur cathode catalysts, thereby contributing to the realization of high-performance Li-S batteries.