Conductive TiN thin layer-coated nitrogen-doped anatase TiO2 as high-performance anode materials for sodium-ion batteries

Nitrogen-doped anatase titanium oxide (N-TiO2) with enhanced electronic conductivity induced by titanium nitride (TiN) thin layer coating was employed as high-performance anode material for sodium-ion batteries. The TiN thin layer can not only dramatically increase the electronic conductivity among crystal grains but also alleviate the volume expansion to consolidate the structure during long-term sodiation and desodiation process. The composite exhibits an excellent electrochemical performance, delivering a high specific capacity of 226.9mAhg(-1) at 0.1 C and owning excellent rate capability of 158.3mAhg(-1) at 10 C high rate. Moreover, the composite has no obvious capacity decay after 500cycles at 1 C, showing its superior cycling performance. The enhancement of electrochemical performance may be attributed to the faster kinetics of sodium ion sodiation/desodiation, which could be a result of enhanced electronic conductivity due to the formation of TiN thin layer coating.