Effect of High-Molecular-Weight Carbon Sources on the Electrochemical Properties of Li4Ti5O12/C Composite Materials

Lithium titanate-based (Li4Ti5O12/C) composite anode materials have been synthesized by a sol–gel process with the use of high-molecular-weight compounds (polystyrene, polyethylene glycol, or polyvinylidene fluoride) as carbon sources. The composites have been characterized by X-ray diffraction, scanning electron microscopy, Raman spectroscopy, and electrochemical testing. The use of the carbon sources leads to the formation of a highly conductive carbon coating on the surface of the lithium titanate particles and improves the electrochemical performance of the materials. The highest reversible discharge capacity at high current densities is offered by the materials prepared using 5 wt % polystyrene or polyethylene glycol (75 and 70 mAh/g, respectively, at 3200 mA/g).