Structure stabilization of LiMn 2O 4 cathode material by bimetal dopants

Abstract

The structural changes of spinel Li 1.02Mn 2O 4 and Li 1.02Co 0.11Ni 0.04Mn 1.85O 4 cathode materials have been studied by synchrotron powder X-ray diffraction and differential scanning calorimetry (DSC) measurements. The results show that spinel Li 1.02Mn 2O 4 undergoes a phase transition from cubic ( Fd3 m) to orthorhombic symmetry ( Fddd) at T=285 K. However, substitution of a small amount of Co 3+ and Ni 3+ ions suppresses phase transition and the cubic phase is maintained at low temperature due to a decrease in the concentration of Jahn–Teller active Mn 3+ ions.