ANION-DEFICIENT NON-STOICHIOMETRIC LITHIUM TRANSITION METAL POLYACID COMPOUND AS ELECTRODE ACTIVE MATERIAL, METHOD FOR PREPARING THE SAME, AND ELECTROCHEMICAL DEVICE USING THE SAME

摘要

PURPOSE: An anion-deficient non-stoichiometric lithium transition metal polyacid compound is provided to increase physical and chemical stability compared to a conventional stoichiometric lithium transition metal polyacid compound and to prevent the generation of impurities. CONSTITUTION: A method for preparing an anion-deficient non-stoichiometric lithium transition metal polyacid compound represented by chemical formula 3: Li_(1-x)Fe(PO_4)_(1-a) comprises the steps of: (a) mixing an Fe precursor compound, a polyacid compound containing phosphorus(P), an alkalizer, and a lithium precursor compound to make a lithium iron phosphate compound precursor; (b) mixing the lithium iron phosphate compound precursor with water in the reaction conditions of a temperature 200~700 °C and the pressure 180 ~ 550 bar to make and drying a non-stoichiometric lithium iron phosphate compound; and (c) calcining the resultant (b) or granulating and incinerating it.