Ultrathin [110]-Confined Li4Ti5O12 Nanoflakes for High Rate Lithium Storage

Improving the high-rate performance of spinel lithium titanate (Li4Ti5O12, LTO) is one of the critical requirements to promote its practical application in Li-ion batteries (LIBs). Herein, the possible Li+ ion diffusion routes in LTO are theoretically analyzed and compared by computational investigation. The calculations show that the most feasible diffusion path for Li+ ions is along the [110] direction indicated by the lowest energy barrier. Inspired by this prediction, ultrathin [110]-confined LTO nanoflakes are rationally prepared through a function-led targeted synthesis. The [110] orientation of the material sufficiently provides preferable transport channels which can promote the anisotropic diffusion of lithium ions within LTO nanoflakes. Furthermore, the ultrathin 2D nanostructure effectively shortens the diffusion length along the [110] direction, facilitating ion transport across the nanoflakes and thus improving the diffusion kinetics. Owing to these unique features, the LIB composed of optimized [110]-confined LTO exhibits remarkable high rate capability and long-term cycling stability, with a capacity of 146 mAh g(-1) at an ultrahigh rate of 100 C and a capacity retention of 88% even after 1500 cycles at 50 C. The as-prepared [110]-confined LTO nanoflakes have promising applications and show commercial viability for high-power facilities.