Effect of the Carbon Source on the Electrochemical Properties of Li4Ti5O12/C Composites Prepared by Solid-State Synthesis

Resumo

Li₄Ti₅O₁₂/C composite anode materials have been prepared by solid-state reactions using lithium- or titanium-containing reagents (lithium lactate, acetate, and acetylacetonate or titanium oxyacetylacetonate) not only as precursors for the synthesis of lithium titanate but also as carbon sources. In addition, two surfactants, Pluronic 123 (P123) and cetyltrimethylammonium bromide, have been used as carbon sources. The composites have been characterized by X-ray diffraction, scanning electron microscopy, and Raman spectroscopy, and their electrochemical properties have been studied. The results demonstrate that the best electrochemical performance is offered by the materials prepared using P123. In particular, the discharge capacity of the Li₄Ti₅O₁₂/C material prepared using TiO₂/P123 and lithium lactate is 119 and 44 mAh/g at current densities of 200 and 3200 mA/g, respectively. The materials prepared using lithium and titanium acetylacetonates have high carbon content and undergo more severe degradation during cycling at high current densities.