Relative Impact of Al or Mg Substitution on the Thermal Stability of LiCo[sub 1−z]M[sub z]O[sub 2] (M=Al or Mg) by Accelerating Rate Calorimetry

Al- or Mg-substituted Li Co 1 − z M z O 2 ( M = Al or Mg) ( z = 0 , 0.05 , 0.1 ) samples were synthesized by a coprecipitation-based method followed by heating with Li O H ⋅ H 2 O at 500 ° C for 3 h and again at 900 ° C for 3 h . Electrochemical studies showed that Al or Mg substitution reduces the initial discharge capacity of Li Co 1 − z M z O 2 cells but does not strongly impact their cycle life. The effects of Al or Mg substitution on the thermal stability of charged Li Co 1 − z M z O 2 were studied by accelerating rate calorimetry and indicate that Al substitution is far more effective than Mg substitution in improving the thermal stability of Li Co 1 − z M z O 2 .