Electrochemical performance and low discharge cut-off voltage behavior of ruthenium doped Li4Ti5O12 with improved energy density

Pristine Li4Ti5O12 (LTO) and Ru-doped Li4Ti5O12 with the composition of Li4Ti4.95Ru0.05O12 (Ru-doped LTO) are synthesized by solid-state reaction. Ru doping into the lattice of LTO affects the electronic structure of LTO, leading to the modification of optical properties and improvement in electrochemical performance. The variations between pristine LTO and Ru-doped LTO in optical properties are investigated by UV–vis and Raman spectroscopy. In addition, the related microstructure is characterized by XRD, SEM and TEM. The enhancement in electronic conductivity of Ru-doped LTO can provide the discharge capacities of 222, 183 and 132 mAh/g at 1C, 5C and 10C, respectively, during the voltage window of 0.01–2.5 V. Furthermore, the capacity retentions are 95, 92 and 86% for 1C, 5C and 10C rates, respectively, at 100th cycles. The significant improvement in electrochemical performance demonstrates that ruthenium doped lithium titanate is promising as a high rate anode for lithium ion batteries.