Synthesis of Mg-doped LiNi0.8Co0.15Al0.05O2 oxide and its electrochemical behavior in high-voltage lithium-ion batteries

Abstract

Mg-doped LiNi0.8Co0.15Al0.05O2 (NCA) cathode material is synthesized from Mg and Li co-coated Ni0.8Co0.15Al0.05(OH)2 precursor. X-ray diffraction (XRD) results indicate that the Mg-doped samples are indexed with hexagonal layered structure and no other impurity peak is found. Moreover, both the lattice parameters a and c increase as the quantity of Mg dopant grows. Scanning electron microscope (SEM) results reveal that the morphologies of the Mg-doped samples are almost the same as that of the pristine one. Electrochemical characterizations show that the Mg-doping leads to higher activation energy for the migration of Li-ions, and suppresses the phase transition between H2 and H3. Furthermore, the pristine and 1 at% Mg-doped samples are selected for studying the degradation behavior at higher upper cutoff potentials. When charged to higher cutoff potentials, the Mg-doped NCA cathode exhibits less capacity fading during cycling than the pristine one.