Lithium Metal Phosphor Oxide Synthesis via Shearing Force
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Solution Overview
Problem
Current methods for preparing lithium metal phosphor oxide, such as solid-state reaction and sol-gel methods, face challenges including high heat treatment temperatures, high raw material costs, and difficulties in achieving uniform nano-particles and surface conductivity, which increase process costs and degrade price competitiveness.
Innovation Solution
A method involving the use of crystalline iron phosphate or metal-doped crystalline iron phosphate as a precursor, where a high-gravity shearing force is applied to form amorphous nano-sized particles, which are then crystallized and mixed with lithium at a lower calcination temperature to produce lithium metal phosphor oxide, reducing process costs and improving battery properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If solid-state reaction method is used to prepare LMP, then uniform nano-particles can be obtained, but high heat treatment temperature is required and price competitiveness is degraded
Solution Approach 1:
The invention changes the chemical composition parameters of the precursor material by incorporating aluminum and/or magnesium elements into the iron phosphate structure. This compositional modification enables the precursor to transform into crystalline LMP at lower temperatures (600-800°C) while maintaining uniform nano-particle morphology, thus resolving the contradiction between particle uniformity and temperature requirement
Solution Approach 2:
The invention performs preliminary structural preparation by creating a precursor with specific Al-Mg-doped iron phosphate composition before the main LMP formation reaction. This preliminary action pre-organizes the atomic structure to facilitate lower-temperature transformation into crystalline LMP, avoiding the need for high-heat treatment while achieving uniform nano-particles
2Manufacturing precision
If sol-gel method is used to prepare LMP, then uniform nano-particles can be obtained, but preparing cost is high due to expensive raw materials and organic solvent
Solution Approach 1:
The invention replaces expensive sol-gel raw materials (metal alkoxides and organic solvents) with inexpensive, readily available inorganic precursors such as iron phosphate, aluminum salt, and magnesium salt. These cheap inorganic materials achieve the same uniform nano-particle formation function without the high cost associated with organic-based sol-gel processes
Solution Approach 2:
The invention changes the material state parameter from organic-based sol-gel system to inorganic-based aqueous or suspension system. This parameter change substitutes expensive organic precursors with inexpensive inorganic salts, dramatically reducing raw material costs while maintaining the ability to produce uniform nano-particles through controlled precipitation and calcination
3Reliability
If solid-state reaction is used to prepare LMP, then LMP can be synthesized, but surface coating with conductive material is difficult due to low electric conductivity
Solution Approach 1:
The invention performs preliminary surface preparation by creating a precursor with specific surface characteristics through Al-Mg doping. The resulting LMP particles have surfaces that are more receptive to conductive material coating, enabling easier and more effective application of conductive layers compared to conventionally prepared LMP
Solution Approach 2:
The invention applies local quality modification by doping specific elements (Al and/or Mg) at specific locations within the precursor structure, particularly at surface regions. This creates localized areas with enhanced reactivity and surface properties that facilitate subsequent conductive material coating, addressing the conductivity issue without requiring complete restructuring of the bulk material
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method allows for the synthesis of crystalline lithium metal phosphor oxide at a lower temperature, reducing process costs and enhancing battery properties and physical properties when used as a cathode active material in lithium secondary batteries.
Implementation Method 1
applying a shearing force to the mixed solution in the reactor during the mixing by the agitator, wherein the packed bed is rotated on a rotation axis and whereby a flow condition having a Reynolds number of 2,000 to 200,000 is formed in the reactor by the shearing force to form a suspension containing amorphous nano-sized iron phosphate precipitate particles
Implementation Method 2
aging the nano-sized amorphous iron phosphate precipitate particles under a condition where crystalline iron phosphate particles are formed
Implementation Method 3
mixing the crystalline iron phosphate particles, respectively metal-doped crystalline iron phosphate particles with a lithium raw material selected from the group consisting of LiOH, Li2CO3, LiCI, and mixtures thereof and performing firing of the mixture
Data Source
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AI summary
The present invention relates to a method for preparing a lithium metal phosphor oxide, the method including: mixing an iron salt solution and a phosphate solution in a reactor; applying a shearing force to the mixed solution in the reactor during the mixing to form a suspension containing nano-sized iron phosphate precipitate particles; obtaining the nano-sized iron phosphate particles from the suspension; and mixing the iron phosphate with a lithium raw material and performing firing, and the lithium metal phosphor oxide according to the present invention has an Equation of LiMnFePO4. Herein, M is selected from the group consisting of Ni, Co, Mn, Cr, Zr, Nb, Cu, V, Ti, Zn, Al, Ga, and Mg, and n is in a range of 0 to 1. According to the present invention, since calcination is performed at a temperature that is lower than that of another existing method, there is an effect of reducing a process cost, and the obtained lithium metal phosphor oxide prepared according to the method of the present invention has an olivine structure type.