Structural investigations of the LTO:Cu thin films

Lithium titanate (Li1+xTi2-xO4) doped with Cu2+ ions was synthesized by sol-gel processing method. The structure was characterized by X-ray Diffraction (XRD). All samples revealed presence of LTO spinel phase. X-ray pattern of undoped LTO was free of any impurities and other crystal phases. Similarly, samples with low amount of copper dopant (x = 0.05 and x = 0.1) exhibit pure LTO spinel phase due to the successful substitution of titanium by copper ions. However, XRD patterns for samples with larger amount of Cu (x = 0.15 and x = 0.2) revealed a mixture of lithium titanate and metal copper oxide. Presence of the Cu metal in samples with high content of copper dopant could be related with inability to substitute a larger number of titanium ions by copper.