Activating Inert Metallic Compounds for High-Rate Lithium-Sulfur Batteries Through In Situ Etching of Extrinsic Metal.

Surface reactions constitute the foundation of various energy conversion/storage technologies, such as the lithium-sulfur (Li-S) batteries. To expedite surface reactions for high-rate battery applications demands in-depth understanding of reaction kinetics and rational catalyst design. Now an in situ extrinsic-metal etching strategy is used to activate an inert monometal nitride of hexagonal Ni ₃ N through iron-incorporated cubic Ni ₃ FeN. In situ etched Ni ₃ FeN regulates polysulfide-involving surface reactions at high rates. Electron microscopy was used to unveil the mechanism of in situ catalyst transformation. The Li-S batteries modified with Ni ₃ FeN exhibited superb rate capability, remarkable cycling stability at a high sulfur loading of 4.8 mg cm ^-2 , and lean-electrolyte operability. This work opens up the exploration of multimetallic alloys and compounds as kinetic regulators for high-rate Li-S batteries and also elucidates catalytic surface reactions and the role of defect chemistry.
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