Thermal behavior and the decomposition mechanism of electrochemically delithiated Li1−xNiO2

Thermal behavior of Li1−xNiO2 (image or C2/m) up to 400°C was studied using thermogravimetry (TG), differential scanning calorimetry (DSC), and high-temperature X-ray diffraction measurements and its decomposition mechanism was proposed. Delithiated Li1−xNiO2 was thermally decomposed to LiNi2O4 spinel (Fd3m) at the temperature range of 180–250°C. For x≤0.5, Li1−xNiO2 was decomposed to LiNiO2 and LiNi2O4 and the fraction of the spinel in the decomposed product increased almost linearly with x. For 0.5