Improving high-voltage cycling performance of nickel-rich NMC layered oxide cathodes for rechargeable lithium–ion batteries by Mg and Zr co-doping

Regarding the cost and safety concerns arising together with the increasing demands on lithium–ion batteries, high energy density Ni-rich LiNi0.8Co0.1Mn0.1O2 (NMC811) materials are of substantial interest as cathode materials for the next-generation commercial lithium–ion batteries. However, their low cycling stability hinders their use in large-scale applications (Schipper et al., 2018). In this work, we report two NMC811 materials, pristine and Mg/Zr co-doped, both synthesized through a facile sol-gel method followed by a stepwise calcination process. The doped cathode presents enhanced structural stability and shows a specific capacity of 232 mAh/g, at 0.1C and high charge cut-off voltage of 4.8 V vs. Li+/Li, and significant good cycling stability after 100 cycles; better than pristine NMC811. To unravel the origin of the enhancement, we have investigated the ionic and electronic transport properties by means of electrochemical impedance spectroscopy measurements, as well as the behavior of the electrode–electrolyte interphase layer.