Method for preparing Li.sub.1+x Mn.sub.2-x-y M.sub.y O.sub.4 for use in lithium batteries

A methed for making an insertion compound having the formula Li.sub.1+x Mn.sub.2-x-y M.sub.y O.sub.4 wherein M is a transition metal, x is a number greater than zero and less than 0.33, y is a number greater than or equal to zero and less than about 1, the insertion compound having a spinel-phase crystal structure, and a maximum critical temperature for phase stability T.sub.c ;

• said method comprising selecting a process from the group consisting of:
• (a) (1) heating a stoichiometric mixture of a first lithium salt and a first manganese compound at a temperature in the range from greater than T.sub.c but less than about 900.degree. C. so that an intermediate compound and having the approximate formula Li.sub.1 Mn.sub.2-y M.sub.y O.sub.4 and a spinel-phase crystal structure is obtained;
• (2) mixing a stoichiometric amount of the intermediate compound and a second lithium salt selected to obtain said insertion compound at a temperature less than T.sub.c ;
• and
• (3) heating the stoichiometric amount of said intermediate compound and said second lithium salt at a temperature in the range from greater than 400.degree. C. to less than about T.sub.c so that said insertion compound having the formula Li.sub.1+x Mn.sub.2-x-y M.sub.y O.sub.4 is obtained;
• and
• (b) heating a stoichiometric mixture of LiCl and a second manganese compound at a reaction temperature in the range from greater than about 400.degree. C. to less than about T.sub.c, so that said insertion compound having the formula Li.sub.1+x Mn.sub.2-x-y M.sub.y O.sub.4 is obtained.