LAUSR

Exploring efficient electrocatalysts for lithium-sulfur (Li-S) batteries is of great significance for the sulfur/polysulfide/sulfide multiphase conversion. Herein, we report nickel-iron intermetallic (Ni3Fe) as a novel electrocatalyst to trigger the highly efficient polysulfide-involving interfacial reactions. The incorporation of iron into cubic nickel phase can induce strong electronic interaction and lattice distortion, thereby activating the inferior Ni phase to catalytically active Ni3Fe phase. Kinetics investigations reveal that Ni3Fe phase promote the redox kinetics of the multiphase conversion of Li-S electrochemistry. As a result, the Li-S cells assembled with a 70 wt%-sulfur cathode and Ni3Fe modified separator deliver initial capacities of 1310.3 mAh g-1 at 0.1 C and 598 mAh g-1 at 4 C with superb rate capability, and a long cycle life of 1000 cycles at 1 C with a low capacity fading rate of ~0.034 per cycle. More impressively, the Ni3Fe catalyzed cells exhibit outstanding performance even at harsh working conditions, such as high sulfur loading (7.7 mg cm-2) or lean electrolyte/sulfur ratio (~6 μL mg-1). This work provides a new concept on exploring advanced intermetallic catalyst for high-rate and long-life Li-S batteries.