Hydrothermal synthesis of Li4Ti5O12/C nanostructured composites: Morphology and electrochemical performance

Li4Ti5O12/C composites with low (3 wt.%) and high (33 wt.%) carbon black content as well as carbon-free Li4Ti5O12 were prepared in two steps under identical conditions: hydrothermal reaction at 130 °C and post-calcination at 400 °C. The X-ray diffraction experiments confirmed the spinel structure of Li4Ti5O12 in all samples. The carbon content altered significantly the morphology of obtained micro/nanoparticles. The Li4Ti5O12/C composite with the high carbon content showed the highest electrical conductivity (2.0 S cm−1), and displayed also extraordinary electrochemical performance: the cyclovoltammograms consisted of well defined reversible redox peaks at a scan rate as high as 10 mV s−1, while, by galvanostatic cycling, the coulombic capacity of 150 mAh g−1 was evidenced at a discharging rate of 10 C.

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► Nanostructured composite Li4Ti5O12/C was obtained hydrothermally.
► The amount of carbon black influenced significantly the morphology of the composite.
► Rate capability of Li4Ti5O12 was improved by the synthesis in presence of carbon black.
► Coulombic capacity of 150 mAh g−1 was obtained at a discharging rate of even 10 C.