Enhanced Electrochemical Performance of Mg-Doped P2–Na0.7[Ni0.3Mn0.6Fe0.1]O2 Cobalt-Free Cathode Materials for Sodium-Ion Batteries

In this study, cobalt-free P2–Na0.7[Ni0.3Mn0.6Fe0.1]O2 (NFM) cathode material is synthesized by a cost-effective and easy solid-state reaction route and its structure is stabilized by Mg-doping. The doping content is optimized by evaluating the physical and electrochemical performances of the series of Mg-doped (Mg = 0.05, 0.10, 0.15) cathode. The structural, morphological, and electronic properties of the cathode materials were characterized using various analytical techniques including X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Electrochemical measurements, including cyclic voltammetry (CV) and galvanostatic charge/discharge, were conducted to assess the electrochemical performance of pristine as well as doped cathode materials. It is observed that Mg-doped cathodes exhibited enhanced capacity and cycle life compared to the pristine counterpart, with NFMMg10 demonstrating the best performance. The optimized Mg-doped NFMMg10 sample shows a maximum discharge capacity of 184 mAh g–1 at 0.05C and 75% capacity retention over 1000 cycles.