Ultrahigh lithiation dynamics of Li 4 Ti 5 O 12 as an anode material with open diffusion channels induced by chemical presodiation

Spinel lithium titanate (Li 4 Ti 5 O 12 , LTO), with the merits of safety operation voltage, stable crystal structure, and minor lattice volume changes, becomes an optimal anode material for high-power Li-ion batteries. However, the inherent wide bandgap and low lithiation reactivity of Li 4 Ti 5 O 12 bring about poor conductivity and lithiation dynamics, limiting its further applications. Herein, we design and prepare unique Li 4 Ti 5 O 12 anode materials with extremely low dopant content of Na + utilizing the amorphous precursors. The resultant Li 4 Na 0.008 Ti 5 O 12.004 sample (denoted as NLTO-0.008) presents superior rate performances and cycle ability, with a reversible capacity of 149.4 mAh·g −1 at the current rate of 10.0C. NLTO-0.008 retains the charge capacity of 151.3 mAh·g −1 with a capacity loss of 0.5% after 1000 cycles at the current rate of 1.0C (charge) /10.0C (discharge). The kinetic studies furtherly demonstrate that the lithiation reaction energy and diffusion energy barrier decrease by 28.8% and 30%, respectively. Crystal structure analysis indicates that Na + occupies the 16d Li site and forms distorted LiO 4 tetrahedron and TiO 6 octahedron. This lattice distortion forms open diffusion channels, thus enhancing the Li + diffusion dynamics and decreasing the lithiation reaction energy barrier for Li 4 Ti 5 O 12 . Therefore, the pre-sodiation strategy may arouse great interest in understanding and developing intercalation-type transition-metal-based electrode materials in high-power lithium-ion batteries. Graphical abstract