Li₄Ti₅O₁₂-TiO₂ nanocomposites represent highly promising materials for energy storage applications owing to their attractive electrochemical properties. However, precisely optimizing their morphology and compositions is essential. In this study, the effects of lithium content on the synthesis of the Li₄Ti₅O₁₂-TiO₂ nanocomposites prepared by the hydrothermal method were investigated. The samples were prepared using different molar ratios of LiOH·H₂O: tertbutyl titanate (TBT) (4:5, 6:5, 8:5, 10:5, and 12:5) using a hydrothermal process at 180 ℃ for 12 h, followed by a calcination step. The microstructure, phase analysis, and morphology of the samples were investigated using X-ray diffraction (XRD), Raman spectroscopy, and field-emission scanning electron microscopy (FESEM) analyses. XRD results showed a phase evolution from an anatase-rich TiO₂ (at a ratio of 4:5) to a Li₄Ti₅O₁₂-dominated nanocomposite (at a ratio of 12:5) with a minor TiO₂ rutile phase. Also, the crystallite size of the Li₄Ti₅O₁₂ phase first increased to a maximum value of 47.3 nm and then decreased to 20-21 nm at higher ratios. FESEM images revealed a growth in particle size of the samples from 138 to 196 nm, by increasing the ratio from 4:5 to 6:5, and then a reduction of particle size to about 55 nm by using higher ratios. The results showed that for achieving Li₄Ti₅O₁₂-TiO₂ rutile nanocomposites with nanoscale particles, higher LiOH·H₂O:TBT ratios are preferred.