LiCo x Mn2−x O4 (x=0, 1/9, 1/6) powders have been synthesized by an oxalate precipitation method. Single phase spinel LiCo x Mn2−x O4 is formed at temperatures as low as 450°C. Fourier transform infrared analysis shows that the spinel powder prepared at 600°C has better phase quality than the powder prepared at 750°C by a conventional solid-state reaction. X-ray diffraction and thermal gravimetric-differential thermal analysis show phase transition and impurity phase formation at three temperatures. It is also found that spinel phase stability increases with increase in cobalt (Co) content. The effects of Co content on the spinel lattice constant, high temperature stability, transition temperature and capacity on cycling are investigated.