Synthesis by citric acid sol–gel method and electrochemical properties of Li4Ti5O12 anode material for lithium-ion battery

Abstract Spinel Li 4 Ti 5 O 12 particles have been synthesized by a sol–gel method with citric acid as a chelating agent and Li 2 CO 3 and tetrabutyl titanate (Ti(OC 4 H 9 ) 4 ) as starting materials. The samples have been characterized by means of IR, XRD, XPS and SEM. These analyses indicated that the prepared Li–Ti–O powder belonged to a spinel structure and had a uniform cubic morphology with an average particle size of 500 nm. Citric acid has a great effect on obtaining excellent phase purity and good stoichiometric inorganic oxides. Its electrochemical behavior was evaluated in a liquid electrolyte in lithium-ion batteries. At a voltage plateau located at 1.55 V(versus Li), the Li 4 Ti 5 O 12 electrode exhibited an initial discharge capacity of 167 mAh g −1 and a subsequent charge capacity of 151 mAh g −1 . The very flat discharge and charge curves indicated that the electrochemical reaction based on Ti 4+ /Ti 3+ redox couple was a typical two-phase reaction. The results of cyclic voltammetry for Li 4 Ti 5 O 12 showed that at the potential range from 1.5 to 1.7 V (versus Li), there was a pair of reversible redox peaks correspond to the process of Li + intercalation and de-intercalation in the spinel Li–Ti–O oxides.