MANGANESE IRON AMMONIUM PHOSPHATE, METHOD FOR PRODUCING SAME, POSITIVE ELECTRODE ACTIVE MATERIAL FOR LITHIUM SECONDARY BATTERIES USING MANGANESE IRON AMMONIUM PHOSPHATE, METHOD FOR PRODUCING POSITIVE ELECTRODE ACTIVE MATERIAL FOR LITHIUM SECONDARY BATTERIES USING MANGANESE IRON AMMONIUM PHOSPHATE, AND LITHIUM SECONDARY BATTERY USING POSITIVE ELECTRODE ACTIVE MATERIAL FOR LITHIUM SECONDARY BATTERIES USING MANGANESE IRON AMMONIUM PHOSPHATE

摘要

Provided are: a positive electrode active material for lithium secondary batteries, which is formed of a composite lithium manganese iron phosphate, which has fine particle diameters, and which exhibits excellent battery characteristics such as high capacity and high output in cases when used as a positive electrode active material; and a method for producing a positive electrode active material for lithium secondary batteries, which uses, as a precursor, a fine manganese iron ammonium phosphate that has a uniform composition.A method for producing a precursor of a positive electrode active material for lithium secondary batteries, which is a method for producing a manganese iron ammonium phosphate, said method being characterized by comprising: a mixed solution preparation step wherein a mixed solution of divalent Mn ions, Fe ions and phosphate ions is prepared; and a crystallization step wherein a manganese iron ammonium phosphate represented by general formula NH₄Mn_xFe_1-xPO₄∙H₂O (wherein 0 x 1) is obtained by coprecipitation by adding ammonia to the mixed solution so as to adjust the pH thereof within the range of 7-9.