Influence of conductive additives and surface fluorination on the charge/discharge behavior of lithium titanate (Li4/3Ti5/3O4)

Effect of conductive additives and surface modification with NF3 and ClF3 on the charge/discharge behavior of Li4/3Ti5/3O4 (≈4.6 μm) was investigated using vapor grown carbon fiber (VGCF) and acetylene black (AB). VGCF and mixtures of VGCF and AB increased charge capacities of original Li4/3Ti5/3O4 and those fluorinated with NF3 by improving the electric contact between Li4/3Ti5/3O4 particles and nickel current collector. Surface fluorination increased meso-pore with diameter of 2 nm and surface area of Li4/3Ti5/3O4, which led to the increase in first charge capacities of Li4/3Ti5/3O4 samples fluorinated by NF3 at high current densities of 300 and 600 mA g−1. The result shows that NF3 is the better fluorinating agent for Li4/3Ti5/3O4 than ClF3.