Synthesis of Li4Ti5O12 fibers as a high-rate electrode material for lithium-ion batteries

Porous lithium titanate (Li4Ti5O12) fibers, composed of interconnected nanoparticles, are synthesized by thermally treating electrospun precursor fibers and utilized as an energy storage material for rechargeable lithium-ion batteries. The material is characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and thermal analysis. Scanning electron microscopy results show that the Li4Ti5O12 fibers calcined at 700 °C have an average diameter of 230 nm. Especially, the individual fiber is composed of nanoparticles with an average diameter of 47.5 nm. Electrochemical properties of the material are evaluated using cyclic voltammetry, galvanostatic cycling, and electrochemical impedance spectroscopy. The results show that as-prepared Li4Ti5O12 exhibits good cycling capacity and rate capability. At the charge–discharge rate of 0.2, 0.5, 1, 2, 10, 20, 40, and 60 C, its discharge capacities are 172.4, 168.2, 163.3, 155.9, 138.7, 123.4, 108.8, and 90.4 mAh g−1, respectively. After 300 cycles at 20 C, it remained at 120.1 mAh g−1. The obtained results thus strongly support that the electrospun Li4Ti5O12 fibers could be one of the most promising candidate anode materials for lithium-ion batteries in electric vehicles.