Thermal and structural stabilities of Li x CoO 2 cathode for li secondary battery studied by a temperature programmed reduction

D. H. Jung, Nurzhan Umirov, T. Kim, Zhumabay Bakenov, J. S. Kim, S. S. Kim

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Temperature programmed reduction (TPR) method was introduced to analyze the structural change and thermal stability of Li x CoO 2 (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 2 –like to Co 3 O 4 –like phase which is similar reduction patterns of CoO 2 phase resulting from delithiation of LCO structure. The 2 nd reduction peak at 300~375 °C corresponds to the reduction of Co 3 O 4 –like phase to CoO–like phase. TPR results indicate the thermal instability of delithiated LCO driven by CoO 2 –like phase on the surface of the delithiated LCO. In the TPR kinetics, the activation energies (E a ) obtained for as-synthesized LCO were 105.6 and 82.7 kJ mol -1 for T m_H1 and T m_H2 , respectively, whereas E a for the delithiated LCO were 93.2, 124.1 and 216.3 kJ mol -1 for T m_L1 , T m_L2 and T m_L3 , 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.

Original languageEnglish
Pages (from-to)3-12
Number of pages10
JournalEurasian Chemico-Technological Journal
Volume21
Issue number1
DOIs
Publication statusPublished - Jan 1 2019

Keywords

  • Lithium cobalt oxide
  • Secondary battery
  • Temperature programmed reduction
  • Thermal stability

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Science(all)
  • Condensed Matter Physics

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