In this work we report the synthesis and the characterization of black anatase TiO2. We show that this material displays a nanostructured architecture, with an electro-conducting trivalent Ti. The presence of trivalent Ti in this structure narrows the inherent high band gap energy to a semiconductor level, reaching a value as low as 1.8 eV, resulting in the very high electrical conductivity of 8 × 10−2 S cm−1. These extraordinary electro-conducting physical properties ensure an ultra fast Li+ insertion into and extraction from the host structure of anatase TiO2 making it a unique, high rate electrode, delivering at a 100 C-rate (20 A g−1) a discharge capacity of 127 mA h (g-TiO2)−1 with approximately 86% retention during 100 charge–discharge cycles at 25 °C and approximately 84% retention at −20 °C.
