High-entropy stabilized oxides derived via a low-temperature template route for high-performance lithium-sulfur batteries

It is a long-standing issue that the sluggish polysulfide conversion and adverse shuttling effects impede the development of lithium-sulfur (Li-S) batteries with high energy density and cycling stability, which necessitate the exploration of new electrocatalysts to facilitate the practical applications of Li-S batteries. Herein, a single-phase high-entropy stabilized oxide (Ni0.2Co0.2Cu0.2Mg0.2Zn0.2)O (HEO850) is successfully prepared through a novel low-temperature annealing strategy from a self-sacrificing metal-organic frameworks (MOFs) template and then integrated into the sulfur host, where it functions as both the catalytic converter and chemical inhibitor towards the shuttle species. Furthermore, the synergistic contribution of randomly dispersed metal elements and the exposure of affluent active sites enable the chemical encapsulation of soluble polysulfides and accelerate conversion kinetics. The HEO850/S/KB cathode (KB: ketjen black; sulfur content: 70 wt.%) delivers a substantially higher initial specific discharge capacity of similar to 1244 mAh g(-1) in comparison to MEO/S/KB (MEO: medium entropy oxide; similar to 980 mAh g(-1)), LEO/S/KB (LEO: low entropy oxide; similar to 908 mAh g(-1)), and routine S/KB cathodes (similar to 966 mAh g(-1)), which is well retained at similar to 784 mAh g(-1) after 800 cycles at 0.5 C with a low capacity decay rate of similar to 0.043% per cycle. Moreover, when the HEO850/S/KB cathode is processed with a high areal sulfur loading (similar to 4.4 mg cm(-2)), the resulting Li-S battery also performs well, with a high initial specific capacity of similar to 1044 mAh g(-1) at 0.1 C and 85% capacity retention after 100 cycles. This study highlights the potential application of HEOs in enhancing the performance of Li-S batteries and provides a novel strategy in synthesizing the HEOs at a relatively low annealing temperature for various energy conversion and storage applications.

Automated summary

The development of lithium-sulfur (Li-S) batteries with high energy density and cycling stability is hindered by the slow polysulfide conversion and adverse shuttling effects. Therefore, new electrocatalysts are needed to facilitate the practical applications of Li-S batteries. In this study, a single-phase high-entropy stabilized oxide (Ni0.2Co0.2Cu0.2Mg0.2Zn0.2)O is prepared and integrated into the sulfur host, functioning as both the catalytic converter and chemical inhibitor towards the shuttle species. The resulting cathode exhibits significantly improved discharge capacity and cycling stability compared to other cathodes, demonstrating the potential application of high-entropy oxides (HEOs) in enhancing the performance of Li-S batteries.