Robust electrochemistry of black TiO2 as stable and high-rate negative electrode for lithium-ion batteries

Abstract

Abstract Electrochemically stable black TiO2 composed of Ti3+ ions and oxygen vacancies is successfully synthesized by a facile and economic sol–gel method followed by calcination in nitrogen atmosphere at 400 °C for 2 h. Several physicochemical techniques are probed to validate the desired state of the obtained material. The material is formed in a pure state with an average size of 10 nm. The electrochemical studies are conducted for its use as negative electrode for Li-ion batteries. At high current rate of 5 C, the electrodes deliver a high discharge capacity of 226 mA h g−1 even after 150 cycles. Similarly, the electrodes also deliver discharge capacities of 197 and 153 mA h g−1 at current rates of 7 C and 10 C, respectively. The robust electrochemical properties of black TiO2 including large specific capacities at high current rates and high stability are ascribed to the formation of defective structure, conductive Ti3+ ions and oxygen vacancies.

Keywords

• Black TiO2
• High-rate negative electrode
• Lithium-ion battery
• Ti3+ ions