Anionic oxygen vacancies in Nb2O5-x/carbon hybrid host endow rapid catalytic behaviors for high-performance high areal loading lithium sulfur pouch cell

The development of lithium/sulfur batteries has been hindered by notorious shuttling effect and sluggish electrochemical conversion kinetics owing to high barrier of lithium ion transport behaviors. In this work, anionic oxygen vacancies in niobium oxide nanoparticle is fabricated on a high-conductive hierarchical porous nano-carbon as a sulfur anchor and lithium ion accelerator. As evidenced by optical coloration and electrochemical measurements, the oxygen-deficient electrocatalyst shows much stronger interaction ability to polysulfides and endows superior catalytic ability of propelling ion kinetics and facilitating the precipitation of Li2S. Theoretical simulations have also revealed that Nb-S bonds are formed when polysulfides interacts with AOV-Nb2O5-x catalyst. Consequently, the as-prepared sulfur cathode exhibits a high initial capacity of 1489 mA h g(-1), corresponding to the theoretical utilization of 89%, and a long life for 600 cycles at 1 C. Enhancing current rate to 5 C, a rate capacity of 899 mA h g(-1) is obtained, demonstrating rapid conversion kinetics. Impressively, even increasing the areal loading to 4.2 mg cm(-2) with the lean electrolyte, the pouch cell can still exhibit the initial areal capacity of 3.54 mA h cm(-2) at 0.343 mA cm(-2) and stabilize for several tens of cycles, providing the promise for fast-charge batteries.

Automated summary

An oxygen-deficient electrocatalyst was developed to enhance the electrochemical performance in lithium/sulfur batteries, improving ion transport and catalytic reactions to achieve high capacity and long cycle life.