Heat of formation for LiMyMn2-yO4 (M = Co, Cr, Li, Mg, Ni) spinel solid solution

The enthalpy of formation for LiMyMn2-yO4 (M=Co, Cr, Li, Mg, Ni) was measur ed by a Tian-Calvet type high temperature isothermal microcalorimeter. The standard enthalpy of formation for LiMn2O4 at 876 K was evaluated to be Del ta H-f(o)=-1404.2+/-6.4 kJmol(-1). The partial substitution of Co and Ni fo r Mn decreased the absolute Delta H-f(o) value, while that of Cr and Mg for Mn increased the absolute Delta H-f(o) value. Inthe case of the partial su bstitution of Li for Mn, no marked change in Delta H-f(o) could be observed .