Titanium niobium oxide (TiNb2O7, TNO) has emerged as a competitor for Li4Ti5O12 (LTO) anode material for the next-generation high energy solid-state batteries. However, the usage of TNO is mainly limited by its low electronic conductivity and low lithium-ion diffusivity, which need to be improved for efficient electrochemical kinetics. Amorphous energy storage materials have been widely considered as alternatives. Here, we report the fabrication of amorphous TNO thin films and their electrochemical performance in half-cell rechargeable Li-ion thin film batteries. The amorphous TNO thin films exhibit: a high discharging capacity of 226 mu Ah/mu m cm(2) (similar to 460 mAh/g) at 17 mu A/cm(2) current density, the high coulombic efficiency of similar to 99%, fast kinetics and stable structure. The amorphous TNO thin films further show a high discharge capacity than amorphous LTO thin films, which is twice greater than crystalline TNO thin films. They offer Li-ion diffusion coefficient of approximate to 10(-13) cm(2)/s, better electron-transfer reaction and high electronic conductivity (approximate to 1 x 10(-9) S/cm) during electrochemical cycling process. The superior electrochemical performance of amorphous TNO thin films are attributed due to their unique disordered structure and morphology features. (C) 2018 The Electrochemical Society.