Stability of LiNi0.8Co0.15Al0.05O2 structure in air and H2 atmospheres at elevated temperatures

LiNi0.8Co0.15Al0.05O2 (LNCA), which is a typical electrode material used in lithium ion batteries, has recently been applied as electrodes for ceramic fuel cells (CFCs). However, the stability of LNCA under CFC operating conditions (i.e., oxidative/reductive atmospheres and elevated temperatures) remains unknown. Herein, we evaluated the structure change of LNCA in air and H2 atmospheres at elevated temperatures. It was found that LNCA exhibited excellent stability in ambient air within a wide temperature range from room temperature to 800 degrees C. However, the H2 atmosphere caused the decomposition of LNCA into LiOH and NiO/CoO solid solution at 300 degrees C, followed by complete reduction to Ni/Co alloy at 600 degrees C. The H2-promoted decomposition is a near second order reaction with activation energy of 223.59 kJ mol-1. These findings indicate that LNCA can be used as a stable cathode and it is a suitable precursor for the in-situ formation of Ni/Co-based anodes for CFCs.

Automated summary

In this study, the structure change of LNCA under elevated temperatures in air and H2 atmospheres was evaluated. It was found that LNCA exhibited excellent stability in ambient air, but decomposed into LiOH and NiO/CoO solid solution in H2 atmosphere, followed by reduction to Ni/Co alloy. LNCA can be a stable cathode and a suitable precursor for the in-situ formation of Ni/Co-based anodes for CFCs.