Self-Nitriding Nanostructured Transition Metal Nitrides in Architected-Carbon Matrices: Unveiling Mechanisms and...

Transition metal nitrides (TMNs) are attractive for cutting-edge energy storage technology, especially emerging lithium-sulfur (Li-S) batteries, owing to their electronic structures resembling those of noble metals. Herein, we unveil the underlying mechanism by which TMNs accelerate reaction kinetics, showcasing two nanostructured TMNs (Mo₂N and VN) embedded within tailored carbon architectures. A novel, unexplored self-nitriding approach was developed to synthesize TMNs with precisely controlled solid (sC) or hollow (hC) carbon architectures, achieved through a colloidal route using imidazolium-based poly(ionic liquid) (PIL) nanoparticles as both a nitrogen-rich template and morphology-directing agent. Compact TMN architectures as sulfur hosts enhance ion diffusion and reaction kinetics, enabling efficient active site access and delivering high performance, such as VN@sC with high initial capacity of 792 mAh g^-1 at 2 C and cyclability up to 650 cycles. Meanwhile, hollow architectures (VN@hC and Mo₂N@hC) featuring hierarchical porous structures serve as cathode electrocatalytic additives, enabling high sulfur loading and delivering an initial capacity of 1143 mAh g^-1 at 0.1 C. Remarkably, this performance is achieved with only 5 wt% additive content in scalable 7.9 × 11 cm² and 12-layer pouch cells designed for drone power systems.