Lithium-Excess Research of Cathode Material Li(2)MnTiO(4) for Lithium-Ion Batteries

Lithium-excess and nano-sized Li(2+x)Mn(1)(−x/2)TiO(4) (x = 0, 0.2, 0.4) cathode materials were synthesized via a sol-gel method. The X-ray diffraction (XRD) experiments indicate that the obtained main phases of Li(2.0)MnTiO(4) and the lithium-excess materials are monoclinic and cubic, respectively. The scanning electron microscope (SEM) images show that the as-prepared particles are well distributed and the primary particles have an average size of about 20–30 nm. The further electrochemical tests reveal that the charge-discharge performance of the material improves remarkably with the lithium content increasing. Particularly, the first discharging capacity at the current of 30 mA g(−1) increases from 112.2 mAh g(−1) of Li(2.0)MnTiO(4) to 187.5 mAh g(−1) of Li(2.4)Mn(0.8)TiO(4). In addition, the ex situ XRD experiments indicate that the monoclinic Li(2)MnTiO(4) tends to transform to an amorphous state with the extraction of lithium ions, while the cubic Li(2)MnTiO(4) phase shows better structural reversibility and stability.