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 purpose of the present invention is to provide a manufacturing method of a lithium iron phosphate cathode active material, a lithium iron phosphate cathode active material manufactured thereby, and a secondary battery manufactured using the same. The present invention provides a manufacturing method of a lithium iron phosphate cathode active material, which comprises a step of manufacturing a mixed solution by mixing a lithium precursor, an iron precursor and a phosphate precursor at 2.5-3.5:1:1.5-2.5 of the mole ratio, and dissolving in a solvent including a dispersant (step 1); and a step of heating the mixed solution of step 1 by using microwaves. Further, the present invention provides a crystalline lithium iron phosphate cathode active material, which is manufactured by the manufacturing method, and comprises first particles having a particle size of 30-200 nm, and second particles having a particle size of 1-5 m, wherein the second particles include multiple first particles, and have a spherical shape. The present invention provides a crystalline lithium iron phosphate cathode active material, which is manufactured by the manufacturing method, and comprises first particles having a particle size of 50-400 nm, and second particles having a particle size of 1-5 m, wherein the second particles include multiple first particles, and have a rod shape. The lithium iron phosphate cathode active material manufactured according to the present invention consists of first particles with a nanometer size, and second particles with a micrometer size, thereby enhancing the electric conductivity, increasing the energy density per volume, and improving the electrode manufacture processibilty. Furthermore, the lithium iron phosphate cathode active material can enhance the performance by improving the size and coagulation of particles by adjusting the mixing ratio of raw materials.