Preparation and electrochemical properties of Co-doped and none-doped Li[LixMn0.65(1−x)Ni0.35(1−x)]O2 cathode materials for lithium battery batteries

Li-rich Mn-based Co-doped Li[LixMn0.65*0.995(1−x)Ni0.35*0.995(1−x)Co0.005(1−x)]O2 and none-doped Li[LixMn0.65(1−x)Ni0.35(1−x)]O2 cathode materials were prepared by a conventional solid-state reaction. The initial charge and discharge test were carried out in the voltage ranges of 2.0–4.8 V and 2.0–4.6 V, then change to 3.0–4.3 V for cyclic test. XRD revealed that all the materials prepared show a (0 0 3) peak at 2θ = 18.5° as a main peak and clearly present a pure hexagonal structure. SEM characterization proved that the as prepared materials are constituted of small and homogenous particles. The Co-doped Li[Li0.0909Mn0.588Ni0.3166Co0.0045]O2 sample expresses highest initial efficiency of 78.8% and highest energy density of 858.4 mWh g−1, while the none-doped Li[Li0.2308Mn0.5Ni0.2692]O2 sample behaves lowest of 56.5% and 590.1 mWh g−1. Furthermore, discharge capacity keeps on going up at the initial stage of cyclic process, which can reach the highest discharge capacity approximately in the fifth cycle. Almost no capacity loss is observed after 30 cycles.

► All the diffraction peaks can be indexed as a layered oxide structure based on a hexagonal α-NaFeO2 structure.
► The initial efficiency can be improved by Co-doping and decreasing of Li excessive.
► The Co-doped Li[Li0.0909Mn0.588Ni0.3166Co0.0045]O2 sample expresses highest initial efficiency of 78.8% and highest energy density of 858.4 mWh g−1.
► The discharge capacity of Co-doped samples behave between 220 and 230 mAh g−1 in 2.0–4.8 V.
► Almost no capacity loss is observed after 30 times cycle.