Synthesis of carbon-coated Li4Ti5O12 nanosheets as anode materials for high-performance lithium-ion batteries.

Pristine and carbon-coated Li 4 Ti 5 O 12 nanosheets are synthesized by a hydrothermal process, followed by calcination at 750 °C for 10 h. The structural properties of the as-prepared composites are characterized systematically by X-ray diffraction (XRD), Raman spectra, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM) and N 2 adsorption–desorption analysis, respectively. Electrochemical lithium insertion/extraction performances are evaluated by the galvanostatic charge/discharge tests, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV), respectively. In comparison, Li 4 Ti 5 O 12 @C exhibits higher specific capacity, better rate capability and capacity retention than the pristine Li 4 Ti 5 O 12 . Analysis from the electrochemical measurements indicates that the enhanced electrochemical performances Li 4 Ti 5 O 12 @C might be attributed to the shorter Li-ion diffusion distance, lower charge-transfer resistance, better electrode kinetics and lower activation energy as a result of thinner nanosheet and the presence of carbon layer. [ABSTRACT FROM AUTHOR]