Multi-ion Modulated Single-step Synthesis of Nanocarbon Embedded with Defect-rich Nanoparticle Catalyst for High Loading Sulfur Cathode.

Oxygen defect-rich iron oxide (ODFO) nanocluster catalyst on nanocarbon is in-situ synthesized with the assistance of multi-ion modulation in one pot. The nanoclusters catalyst is employed to propel electrochemical kinetics in lithium/sulfur batteries. Electrochemical analysis and theoretical simulation evidently verify the critical role of defect sites on catalyzing conversion reactions of sulfur species and reducing energy barriers. As a consequence, the ODFO enhanced sulfur cathode exhibits high specific capacity of 1489 mA h g-1 at 0.1 C; excellent rate performance of 644 mA h g-1 at 10 C; and superior cycling stability with an average capacity fading rate as low as 0.055% per cycle under ultrahigh rate of 10 C. More importantly, even with a high sulfur loading of 11.02 mg cm-2, the Li/S cell can still deliver an areal capacity of 8.7 mA h cm-2 at 0.5 C (9.23 mA cm-2). Such performance is the highest among reported metal oxide-catalyzed sulfur cathodes. This work opens a new route to boosting conversion reaction kinetics by introduction of active oxygen defect sites in electrodes of various emerging ultra-fast batteries.