TY - JOUR AU - Jung, D.-H. AU - Umirov, N. AU - Kim, T. AU - Bakenov, Z. AU - Kim, J.-S. AU - Kim, S.-S. PY - 2019/02/20 Y2 - 2024/03/29 TI - Thermal and Structural Stabilities of LixCoO2 cathode for Li Secondary Battery Studied by a Temperature Programmed Reduction JF - Eurasian Chemico-Technological Journal JA - Eurasian Chem.-Technol. J. VL - 21 IS - 1 SE - Articles DO - 10.18321/ectj780 UR - https://ect-journal.kz/index.php/ectj/article/view/780 SP - 3-12 AB - <p>Temperature programmed reduction (TPR) method was introduced to analyze the structural change and thermal stability of Li<sub><em>x</em></sub>CoO<sub>2</sub> (LCO) cathode material. The reduction peaks of delithiated LCO clearly represented the different phases of LCO. The reduction peak at a temperature below 250 °C can be attributed to the transformation of CoO<sub>2</sub>–like to Co<sub>3</sub>O<sub>4</sub>–like phase which is similar reduction patterns of CoO<sub>2</sub> phase resulting from delithiation of LCO structure. The 2<sup>nd</sup> reduction peak at 300~375 °C corresponds to the reduction of Co<sub>3</sub>O<sub>4</sub>–like phase to CoO–like phase. TPR results indicate the thermal instability of delithiated LCO driven by CoO<sub>2</sub>–like phase on the surface of the delithiated LCO. In the TPR kinetics, the activation energies (<em>E</em><em>a</em>) obtained for as-synthesized LCO were 105.6 and 82.7 kJ mol<sup>-1</sup> for&nbsp;T<sub>m_H1</sub> and T<sub>m_H2</sub>, respectively, whereas <em>E</em><sub><em>a </em></sub>for the delithiated LCO were 93.2, 124.1 and 216.3 kJ mol<sup>-1</sup> for T<sub>m_L1</sub>, T<sub>m_L2</sub> and T<sub>m_L3</sub>, respectively. As a result, the TPR method enables to identify the structural changes and thermal stability of each phase and effectively characterize the distinctive thermal behavior between as-synthesized and delithiated LCO.</p> ER -