Synthesis and electrochemical properties of Li₄Ti₅O₁₂/C composites by sol-gel method

In situ carbon-coated Li₄Ti₅O₁₂ composites were prepared by sol-gel route using citric acid and lauric acid as chelate agent and also carbon sources. The crystal structure, microstructure and electrochemical properties of samples were characterized by XRD, SEM, TEM, TG-DSC and galvanostatically charge-discharge experiments. The effects of the content of carbon sources on the phase structure, the microstructure and electrochemical properties were studied to optimize process. The sample prepared with citric acid to titanium molar ratio CTR=1:6 and lauric acid to titanium molar ratio LTR=1:20 was coated with a carbon layer of 5-10nm, exhibiting the best electrochemical performance. The carbon content of the sample was about 2.3wt%. Its discharge capacity at 1C rates can reach 151.1 mAh/g, respectively. After 50 cycles, fairly stable cycling performance was achieved without obvious capacity fade.