Improved rate capability and cycling stability of novel terbium-doped lithium titanate for lithium-ion batteries

Abstract Li 4 Ti 4.94 Tb 0.06 O 12-δ has been synthesized via a facile co-precipitation method. The structure and morphology of the as-prepared sample have been characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and particle size distribution analysis. The results show that Tb 3+ is successfully doped into the Li 4 Ti 5 O 12 structure and that the average particle size is about 111 nm. Li 4 Ti 4.94 Tb 0.06 O 12-δ exhibits a high initial discharge capacity of 166.5 mAh g −1 at 20 C, and the discharge capacity retention is nearly 93% after 500 cycles. In addition, the sample shows much improved rate capability at 20 C compared with pure Li 4 Ti 5 O 12 . Tb 3+ doping not only enhances the electronic conductivity, but also improves the Li + ion diffusivity in Li 4 Ti 5 O 12 , which indicates that Tb 3+ doping is beneficial for promoting the electrochemical performance of Li 4 Ti 5 O 12 .