On the sol-gel synthesis mechanism of nanostructured Li3.95La0.05Ti4.95Ag0.05O12 with enhanced electrochemical performance for lithium ion battery

A modified sol-gel process using ethylene diamine tetraacetic acid and citric acid as bi-components chelating agent was used to prepare Li3.95La0.05Ti4.95Ag0.05O12 (LLTAO). The reactions between raw materials and the possible route of hydrolysis-sintering processes were detailed analyzed and studied. The phases forming mechanism and structure of the colloidal particles, gel and the precursor were also discussed. Interface reaction between chelating agents and precipitate contributes a lot to the products. XRD, SEM, FT-IR, TEM and TG-DSC were used to characterize the intermediates and final powders. The intermediate product of Li and Ti is in nanometer scale, uniformly distributed in precursor. The La3+ and Ag+ co-doping could greatly improve the electrochemical performance of LTO, which reached the capacity of 179, 168, 163, 151, 133, 109 and 76 mA h g−1 at 0.5C, 1C, 2C, 5C, 10C, 20C and 40C discharge rate, respectively. The electrochemical performance of lithium intercalation/extraction was characterized by electrochemical impedance spectroscopy at room temperature.