Abstract:
본 발명의 목적은 리튬인산철 양극 활물질의 제조방법, 이에 따라 제조되는 리튬인산철 양극 활물질 및 이에 따라 제조되는 2차 전지를 제공하는 데 있다. 이를 위하여 본 발명은 리튬 전구체, 철 전구체 및 인산 전구체를 20 중량% 내지 30 중량%의 농도의 분산제를 포함하는 용매에 녹여 혼합용액을 제조하는 단계(단계 1); 및 상기 단계 1의 혼합 용액을 마이크로파를 이용하여 가열하는 단계(단계 2);를 포함하는 리튬인산철 양극 활물질의 제조방법을 제공한다. 또한, 본 발명은 상기의 방법으로 제조되고, 50 내지 300 nm 범위의 입경을 가지는 1차 입자 및 1 ㎛ 내지 50 ㎛ 범위의 입경을 가지는 2차 입자로 이루어지되, 상기 2차 입자는 복수개의 상기 1차 입자들을 포함하며 구형의 형태를 나타내는 것을 특징으로 하는 결정질 리튬인산철 양극 활물질을 제공한다. 본 발명에 따라 제조된 리튬인산철 양극 활물질은 나노미터 크기의 1차 입자및 마이크로미터 크기의 2차 입자로 구성되어 전기전도도를 개선할 수 있으며, 전극 제조 공정상에서 문제발생율을 저하할 수 있다. 또한, 분산제를 포함하는 용매의 혼합비율 및 마이크로파 가열조건을 조절하여 공정상 경제성이 향상될 수 있다.
Abstract:
Provided in the present invention are a method for producing lithium iron phosphate cathode active materials, lithium iron phosphate cathode active materials produced thereby and production of a secondary battery using the same. For this, the present invention comprises: a process (a first process) of producing a mixed solution by dissolving a lithium precursor, an iron precursor and a phosphate precursor in a solvent having a dispersant with a 20-30 wt% concentration; and a process (a second process) of heating the mixed solution of the first process by using microwaves. Furthermore, the present invention provides crystalline lithium iron phosphate cathode active materials produced through the above-mentioned method, which comprise first particles having a particle diameter between 50 and 300 nm and a second particle having a particle diameter between 1 μm and 50 μm, wherein the second particle includes the plurality of first particles and is a globular shape. The lithium iron phosphate cathode active materials according to the present invention are able to improve electrical conductivity by being made of first particles in a nanometer size and the second particle in a micrometer size, and minimize the possibility of problem occurrence within the electrode production procedures. Furthermore, economic feasibility within the production process can be enhanced by adjusting a mixing ratio of the solution containing a dispersant and controlling a heating condition of the microwaves.
Abstract:
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 μm, 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 μm, 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.