A Dual‐Functional Titanium Nitride Chloride Layered Matrix with Facile Lithium‐Ion Diffusion Path and Decoupled Electron Transport as High‐Capacity Anodes

Abstract Intercalation typed electrodes are expected with low theoretical capacity, which falls behind their high rate performance and stability. In this work, α‐TiNCl, an isoelectronic system of TiO 2 , is designed as a promising high‐capacity intercalation anode. TiNCl features are layered TiN backbone terminated by Cl atoms. While the rocksalt TiN backbones function as electron conductors, the interlayer voids provide Cl‐coordinated Li + sites without strong Li‐Ti repulsion, which proves to be a rapid diffusion path with a low energy barrier (0.06 vs 0.47 eV of TiO 2 ). Therefore, a dual‐functional TiNCl matrix is established for Li + and e – transport. To stabilize the layered structure, TiNCl is scaffolded by an in situ grown TiO 2 coating, which also serves as an electron reservoir during lithiation. The TiNCl‐TiO 2 anode exhibits significantly large Li + intercalation capacity (243% of TiO 2 ) and outstanding battery performance (231 mA h g –1 at ≈17 C for 2500 cycles, 94 mA h g –1 at ≈34 C for 10 000 cycles). The (+) LiCoO 2 || TiNCl‐TiO 2 (–) full battery maintains 170 mA h g –1 for 300 cycles. This work may shed light on the molecular engineering of new compounds for electrodes.