Enhancing the electrochemical performance of commercial TiO2 by eliminating sulfate radicals and coating carbon

- Commercial TiO2 (c-TiO2) exhibits poor electrochemical performance.
- The performance of c-TiO2 is improved by coating carbon at temperatures above 750 °C.
- The removal of SO42− and formation of carbon coating are responsible for the enhanced performance.

Despite the low price of commercial TiO2 (c-TiO2), the poor electrochemical performance restricts its practical application in Li-ion batteries, so clarifying the reasons and taking appropriate measures to improve the performance are of great significance. Herein, c-TiO2 was coated with carbon at 600 and 750 °C using glucose as the carbon source. The product obtained at 750 °C exhibits markedly enhanced reversible capacities and outstanding rate performance compared to that obtained at 600 °C. In terms of the comparative experiments and detailed characterizations by several techniques, the SO42− remained in the c-TiO2 is the dominant impurity affecting the electrochemical performance mostly. The thorough decomposition of SO42− at 750 °C and the formation of carbon coating give rise to the enhanced electronic and ionic conductivities of the c-TiO2, and thus are responsible for the significant improvement in the electrochemical performance. The easy fabrication and the low cost of the raw materials enable the carbon-coated c-TiO2 to industrially apply in the LIBs.