NOVELTY - Preparing an electrode material for battery, comprises: providing a reaction precursor having a crystal structure, where the reaction precursor is sodium (Na) metal oxide compound (I); dispersing the reaction precursor in a solvent and adding a lithium (Li) salt to it, to form a mixed solution; and performing a microwave heating treatment on the mixed solution, where Li+ in the lithium salt are ion exchanged with Na+ in the reaction precursor, to form lithium metal oxide compound (II) as the electrode material.    USE - The electrode material is useful for battery, including fuel cells or lithium ion batteries (claimed).    ADVANTAGE - The method is much simpler, requires a shorter time for the preparation process, effectively eliminates an ion mixing phenomenon, improves the structural stability of the electrode material, improves the performance of the battery, and prolongs the life time of the battery. The method has improved preparation efficiency. The method can be applied in industrial mass production, improves the competitiveness and occupancy in domestic market, since it reduces the manufacturing cost. The electrode material prepared by the microwave-ion exchange process has excellent electrochemical properties.    DETAILED DESCRIPTION - Preparing an electrode material for battery, comprises: providing a reaction precursor having a crystal structure, where the reaction precursor is sodium (Na) metal oxide compound of formula (NaxMyM1zO2) (I); dispersing the reaction precursor in a solvent and adding a lithium (Li) salt to it, to form a mixed solution; and performing a microwave heating treatment on the mixed solution, where Li+ in the lithium salt are ion exchanged with Na+ in the reaction precursor, to form lithium metal oxide compound of formula (LixMyM1zO2) (II) as the electrode material.    M, M1 = metal, where M and M1 are not same, preferably Fe, Co, Ni, Mn, Va, Cr or Al;    x = greater than 0.01 and less than or equal to 1;    z = greater than 0.01 and less than 2; and    y = 1-z or 2-z.