Solid-State Synthesis as a Method for the Substitution of Al for Co in LiNi[sub 1∕3]Mn[sub 1∕3]Co[sub (1∕3−z)]Al[sub z]O[sub 2]

Al was substituted for Co in by two different routes: during coprecipitation of the hydroxide precursor or afterward as introduced during solid-state sintering. The latter method avoids the formation of layered double hydroxides during the coprecipitation, but may not ensure uniform distribution of the Al atoms in the mixed cation layers. The electrochemical performance and thermal stability of Al-substituted was studied by coin cell testing and accelerating rate calorimetry tests, respectively. High resolution compositional analysis showed that the Al distribution was not uniform in material prepared by solid-state synthesis at , unlike materials prepared by coprecipitation at 900 or or by solid-state synthesis at . Nonuniform Al distribution does not affect the electrochemical properties strongly, but has a strong negative impact on the thermal stability of the charged electrode materials. The solid-state sintering substitution of Al for Co can be successful if the sintering temperature is high enough to ensure a uniform Al distribution.