Molten salt synthesis of sodium lithium titanium oxide anode material for lithium ion batteries

Abstract

The sodium lithium titanium oxide with composition Na2Li2Ti6O14 has been synthesized by a molten salt synthesis method using sodium chloride and potassium chloride mixture as a flux medium. Synthetic variables on the synthesis, such as sintering temperature, sintering time and the amount of lithium carbonate, were intensively investigated. Powder X-ray diffraction and scanning electron microscopy images of the reaction products indicates that pure phase sodium lithium titanium oxide has been obtained at 700°C, and impure phase sodium hexatitanate with whiskers produced at higher temperature due to lithium evaporative losses. The results of cyclic voltammetry and discharge–charge tests demonstrate that the synthesized products prepared at various temperatures exhibited electrochemical diversities due to the difference of the components. And the sample obtained at 700°C revealed highly reversible insertion and extraction of Li+ and displayed a single potential plateau at around 1.3V. The product obtained at 700°C for 2h exhibits good cycling properties and retains the specific capacity of 62mAhg−1 after 500 cycles.