THE PREPARING METHOD OF LITHIUM IRON PHOSPHATE CATHODE ACTIVE MATERIALS, THE LITHIUM IRON PHOSPHATE CATHOD ACIVE MATERIALS THEREBY AND THE SECONDARY BATTERY USING THE SAME

摘要

The present invention relates to a manufacturing method of lithium iron phosphate cathode active materials, lithium iron phosphate cathode active materials manufactured thereby, and secondary battery manufactured thereby. More specifically, the manufacturing method of lithium iron phosphate cathode active materials comprises: a first step of manufacturing a mixed solution after dissolving into a solvent containing a dispersing agent by mixing a lithium precursor, an iron precursor, a phosphoric acid precursor, and a citric acid in a mole ratio of 2.5-3.5:1:1.5-2.5:1-1.5; and a second step of heating the mixed solution of the first step using microwaves. The present invention controls a mixing ratio of the lithium precursor, the iron precursor, the phosphoric acid precursor, and the citric acid to a specific range, and comprises the optimal form and size for a first particle of a nanometer size and a second particle of a micrometer size. Therefore, electrical conductivity can be largely improved, energy density per volume can be increased, and problems in a process of electrode manufacture can be reduced. In addition, the lithium iron phosphate cathode active materials can be easily and rapidly manufactured by using microwaves, and effective on improvement of economical efficiency in the process.