Carbon-coated Li4Ti5O12 Anode Materials Synthesized Using H2TiO3 as Ti Source

Two low-cost synthesis routes have been developed to fabricate carbon-coated Li4Ti5O12 by using H2TiO3 instead of anatase TiO2 as Ti source through solid-state reaction process. One route is a direct solid mixture of H2TiO3, Li2CO3 and pitch followed by high-temperature solid-state reaction. The other includes mixture of H2TiO3 and Li2CO3 with pitch dissolved in furanidine under vacuum and the same solid-state reaction procedure is followed after the mixture is totally dried. Microstructural investigations indicate that H2TiO3 exhibits secondary aggregates morphology with primary particle sizes of 10-20 nm. Carbon-coating layers with thickness of 2-3 nm have been observed on Li4Ti5O12 synthesized by the two routes. Cyclic performance, rate capability and electrochemical impedance spectrum of the two Li4Ti5O12/C composites have been performed, which indicate that Li4Ti5O12/C obtained by furanidine-assisted mixture exhibits better electrochemical performance than Li4Ti5O12/C synthesized by direct solid mixture. The possible reasons have been discussed. The low-cost synthesis routes of Li4Ti5O12/C using H2TiO3 as Ti source are expected to be more competitive than the traditional one for practical applications.