Mg-ion batteries are rechargeable aqueous metal-ion batteries (RAMBs) and eco-friendly energy storage devices. Herein, we have fabricated T-MgMn2O4, and T- MgNd0.02Co0.18Mn1.78O4 spinel cathode materials via modifying the sol-gel route. This eco-friendly modified method is low cost, high stability, and low toxicity which is carried out by gamma radiation in the Co60 gamma cell source with a dose rate of 1.2 kGy/h. This method presented good advantages such as lower temperature compared to the solid-state reactions, better homogeneity, improved reactivity, and new compositions, and better control of stoichiometry, particle size, and purity. The structure and morphology of the as-prepared materials were investigated by X-ray diffraction (XRD), electron spin resonance (ESR), Raman, and scanning electron microscope (SEM). The electrochemical properties of the as-prepared materials were discussed. Finally, the charge-transfer resistance (Rct), and the discharge specific capacity at current density 1mA/g for T-MgMn2O4 and T- MgNd0.02Co0.18Mn1.78O44 were 369.8 Ω, 299 mAh/g, and 196.7 Ω, 209 respectively. The capacity fading is reduced by doping with a small concentration of (Nd, and Co) as compared to the pure MgMn2O4 cathodes; construction is suitable for Mg-ion battery applications. A small quantity of rare earth metal elements could improve the stability of the Tetragonal Spinel MgMn2O4 Cathode Material. Moreover, the improvement of the electrochemical performance of the prepared cathodes nanocomposite by gamma-irradiated arises from the enlargement of the effective electrochemical area along with the enhancement of electrochemical impedance.