Influence of Co doping on crystal structure and electrochemical performances of LiNi0.5Mn1.5O4

To investigate the influence of Co doping on spinel LiNi0.5Mn1.5O4 cathode, LiNi0.4Co0.1Mn1.5O4 and LiNi0.35Co0.1Mn1.5O4 were designed and successfully synthesised through a polymer assisted method. Inductively coupled plasma, X-ray diffraction, Fourier transform infrared spectra and X-ray photoelectron spectroscopy tests have been carried out. Results show that the compositions of the synthesised samples are consistent with the designed compositions, and Co doping could decrease the degree of cation ordering; Co doping together with octahedral vacancies could induce higher concentration of Mn3+ in the spinel structure. The result of cyclic voltammetry test suggests LiNi0.35Co0.1Mn1.5O4 has the best conductivity, and LiNi0.35Co0.1Mn1.5O4 exhibited the best rate capability among the three spinel cathodes.