High-Entropy Oxide Nanofibers as Catalytic Host Promising High Volumetric Capacity of Sulfur-Based Composites for Lithium-Sulfur Batteries

The exploration of the appropriate sulfur host with favorablecatalyticactivity and high density is important to enhance the volumetric energydensity of lithium-sulfur (Li-S) batteries. In thiswork, high-entropy oxide (HEO) of (Ni0.2Co0.2Mn0.2Cu0.2Zn0.2)WO4 (HE-CWO)nanofibers is fabricated as the sulfur host for the first time. Themultiple metal cations in the single-phase structure of HE-CWO nanofibersenable strong chemical interaction with soluble lithium polysulfidesand fast conversion kinetics from polysulfides to the final dischargeproduct of Li2S2/Li2S. Therefore,the S/HE-CWO composite exhibits a good rate capacity with 656.3 mAh g(-1) at 5C rate and desirable cycling stabilitywith a slow fading rate of 0.080% per cycle for 500 cycles at 1C rate.Moreover, the tap density of the S/HE-CWO composite reaches 1.98 gcm(-3), nearly twice as high as that of the S/CNTcomposite (0.96 g cm(-3)), leading to a high volumetriccapacity of 1795.3 mA h cm(-3) (-composite). This work affords a promising strategy for improving the volumetricenergy density and electrochemical performance of Li-S batteries..

Automated summary

In this study, high-entropy oxide (HEO) nanofibers were used as sulfur hosts for the first time, showing good rate capacity and cycling stability due to strong chemical interaction with lithium polysulfides. The tap density of the sulfur/HEO composite was also significantly higher than that of the sulfur/CNT composite, leading to a higher volumetric capacity. This research provides a promising strategy for improving the volumetric energy density and electrochemical performance of lithium-sulfur batteries.