Li2CuTi3O8–Li4Ti5O12 double spinel anode material with improved rate performance for Li-ion batteries

Ti-based anode materials with the nominal compositions Li4Ti5CuxO12 + x (x = 0, 0.075, 0.15, 0.3, 0.6, 1.20 and 1.67) were synthesized at 800 °C by a solid-state reaction process. X-ray diffraction analysis indicated that the sintered samples were composed of intergrown spinel-type Li4Ti5O12 and Li2CuTi3O8, and a small amount of Li2O. Scanning electron microscopy, electrical resistance measurement and galvanostatic cell cycling were also employed to characterize the structure and properties of the double spinel samples. It is proposed that the first lithiation of the component Li2CuTi3O8 leads to the in situ production of Cu that can significantly improve the rate performance of Li4Ti5CuxO12 + x. The optimal nominal composition is Li4Ti5Cu0.15O12.15.