Structural and electrochemical properties of LiCoMnO4 doped with Mg, La, and F as a high-voltage cathode material for lithium ion batteries.

• The amount of Li 2 MnO 3 phase is affected by the coprecipitation conditions, synthesis temperature, and introduction of dopants. • LiCoMnO 4 cathode with less Li 2 MnO 3 phase exhibits better electrochemical performance. • Fluorination can suppress the phase decomposition and Li/Co ionic mixing during the redox process and increase structural stability, eventually causing LCMO-1.5F to demonstrate the best electrochemical performance. This study characterizes the relationship between synthesis conditions using the coprecipitation method and the structural/electrochemical properties of LiCoMnO 4. A cathode material, LiCoMnO 4 , prepared at pH 7.7 via coprecipitation and calcinated at 850 °C for 14 h achieved an initial discharge capacity of 114.6 mAh g−1 and a capacity retention rate of 71.3% after 20 cycles. To improve electrochemical performance, LiCoMnO 4 was doped with La, Mg, and F elements. The results showed that the strong ionic bonds of fluorination (M‒F; M =Li, Co, and Mn) can suppress the phase decomposition and Li/Co ionic mixing during the redox process and increase structural stability. Thus, LiCoMnO 4 doped with F demonstrated excellent electrochemical performance compared with that of the other dopants. [ABSTRACT FROM AUTHOR]