Overcoming Ion Transport Barrier by Plasma Heterointerface Engineering: Epitaxial Titanium Carbonitride on Nitrogen‐Doped TiO<sub>2</sub>for High‐Performance Sodium‐Ion Batteries
Qianli Cai, Xinglong Li, Ertao Hu, Zhongyue Wang, Peng Lv, Jiajin Zheng, Kehan Yu, Wei Wei, Kostya Ostrikov
Abstract
Abstract Anatase TiO 2 is a promising anode material for lithium‐ion batteries (LIBs) and sodium‐ion batteries (SIBs) due to its high specific capacity, low cost, and excellent cycle stability. However, low electrical conductivity and poor Na + ion transport in TiO 2 limit its practical applications. Here, substantially boosted Na + ion transport and charge transfer kinetics are demonstrated by constructing a near‐ideal non‐rectifying titanium carbonitride/nitrogen‐doped TiO 2 (TiC x N 1– x /N‐TiO 2 ) heterostructure. Owing to the fast plasma effects and metastable hybrid phases, the TiC x N 1– x is epitaxially grown on TiO 2 . Energy band engineering at the interface induces high electron densities and a strong built‐in electric field, which lowers the Na + diffusion barrier by a factor of 1.7. As a result, the TiC x N 1– x /N‐TiO 2 electrode exhibits excellent electrochemical performance. The reversible specific capacities at rates of 0.1 and 10 C reach 312.3 and 173.7 mAh g −1 , respectively. After 600 cycles of charge and discharge at 10 C, the capacity retention rate is 98.7%. This work discovers an effective non‐equilibrium plasma‐enabled process to construct heterointerfaces that can enhance Na + ion transport and provides generic guidelines for the design of heterostructures for a broader range of energy storage, separation, and other devices that rely on controlled ionic transport.