Preparation of LiFePO4/H2Ti3O7 and LiFePO4/TiO2 nanocomposite by sol-gel method as cathode material for lithium-ion battery

摘要

The sol-gel method is adopted for synthesizing LiFePO4/H2Ti3O7 and LiFePO4/TiO2 nanocomposites and contrasted them with different content. The crystal structure and morphology of the as-synthesized samples are characterized via X-ray diffraction and scanning electron microscope techniques, respectively. It is demonstrated that the structure of composite materials is a single olivine structure without any impurity phases. The specific surface area and pore size of H2Ti3O7 and TiO2 are analyzed using the BET surface area technique and the BJH method, which exhibits that the higher specific surface area is very beneficial to the diffusion of lithium ion. Also, the electrochemical properties are tested by the charge-discharge tests. Two composites show fascinating cycle capacity and charge-discharge performance when the amount of H2Ti3O7 and TiO2 is 1%. Among them, 1% H2Ti3O7 presents a better performance at 0.5 C. The sample delivers a discharge capacity of 161.1 mAh g(-1) (105.83% of the initial capacity is kept after 50 cycles). In conclusion, the proper addition of H2Ti3O7 and TiO2 can effectively facilitate the lithium ion diffusion rate to enhance the electrochemical properties of composites.