Influence of Cr and Mg co-doping on electrochemical performance of quaternary cathode materials for lithium-ion battery

In the present study, a novel layered cathodic compound, Li_1-xNi_0.58Co_0.12Mn_0.19Fe_0.07Cr_0.04Mg_xO₂, was synthesized using an economically feasible oxalic acid co-precipitation method. The microstructure, morphology, and electrochemical properties of the synthesized compounds were studied by X-ray diffraction (XRD), scanning electron microscope (SEM), charge–discharge tests, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). Electrochemical test results showed that the sample containing Cr = 0.04 and Mg = 0.02 exhibited the best electrochemical performance with an initial specific capacity of 181.76 mAh·g⁻¹ at 0.1 C, the capacity retention ratios of 88.81% at 200 cycles at 0.5 C. In addition, the 4Cr-2 Mg electrode exhibits superior rate capability with discharge capacities of 182.56, 171.13, 158.51, 133.41, and 121.01 mAh·g⁻¹ at 0.1, 0.2, 0.5, 1, and 2 C, respectively. Replacing Cr can play an essential role in improving maintenance capacity and cycling behavior. Additionally, the diffusibility of lithium-ion batteries (LIBs) was significantly improved as a result of Mg doping, which could be related to the reduction in Li⁺/Ni²⁺ cation mixing and its ionic radius.