Lithium Battery Precursor XRD Peak Ratio for High Efficiency
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Solution Overview
Problem
Lithium secondary batteries using lithium-containing composite metal oxides as positive electrode active materials face limitations in achieving high initial charging and discharging efficiency.
Innovation Solution
A positive electrode active material precursor with a specific composition and structure, represented by NixCoyMnzMw(OH)2, is used, where the ratio of half widths in X-ray diffraction peaks and secondary particle diameter are optimized to enhance the efficiency of the lithium secondary battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional lithium-containing composite metal oxide is used as positive electrode active material, then manufacturing process is simple, but initial charging and discharging efficiency is insufficient
Solution Approach 1:
The invention changes the crystallite size parameter to a specific range (500-1500 Å) and controls the crystal structure (layered structure with specific XRD peak ratios) to achieve high initial charging and discharging efficiency while maintaining a practical manufacturing process using conventional coprecipitation and calcination methods
Solution Approach 2:
The invention uses composite metal oxide containing multiple elements (Ni, Co, Mn, and optionally Al, Ti, B, etc.) in specific ratios to achieve both high efficiency and stability, combining the benefits of different metals while maintaining ease of manufacture through conventional mixing and processing
2Reliability
If crystallite size is reduced to improve efficiency, then initial charging and discharging efficiency increases, but manufacturing precision requirements increase
Solution Approach 1:
The invention specifies an optimal crystallite size range (500-1500 Å) that balances efficiency improvement with manufacturability, and controls the ratio of XRD peak half-widths (α/β ≥ 0.9) to ensure consistent crystal structure without requiring ultra-precise manufacturing
Solution Approach 2:
The invention performs preliminary control of crystallite size and crystal structure during the precipitation and calcination processes by controlling parameters such as pH, temperature, and calcination conditions, ensuring the final product meets specifications without requiring post-processing adjustments
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
The optimized precursor leads to a positive electrode active material that exhibits high initial charging and discharging efficiency, thermal stability, and improved cycle properties in lithium secondary batteries.
Implementation Method 1
a process of burning the mixture
Implementation Method 2
a ratio (α/β) between a half width α of a peak that is present within a range of a diffraction angle 2θ=19.2±1° and a half width β of a peak that is present within a range of 2θ=38.5±1° is equal to or greater than 0.9 in powder X-ray diffraction measurement using a CuKα beam
Data Source
AI summary
The present invention provides a positive electrode active material precursor for a lithium secondary battery, in which the positive electrode active material precursor is represented by the following composition formula (I), a ratio (α/β) between a half width α of a peak that is present within a range of a diffraction angle 2θ=19.2±1° and a half width β of a peak that is present within a range of 2θ=38.5±1° is equal to or greater than 0.9 in powder X-ray diffraction measurement using a CuKα beam:NixCoyMnzMw(OH)2 (I)[0.7≤x<1.0, 0<y≤0.20, 0≤z≤0.20, 0≤w≤0.1, and x+y+z+w=1 are satisfied, and M is one or more selected from the group consisting of Mg, Ca, Sr, Ba, Ti, Zr, V, Nb, Cr, Mo, W, Fe, Ru, Cu, Zn, B, Al, Ga, Si, Sn, P, and Bi].