High-Nickel Layered Cathode With Controlled Crystallite Distribution
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Solution Overview
Problem
There is a need to enhance the energy density and control the crystallite size distribution of lithium metal composite oxides with high Ni concentration for improved performance in lithium secondary batteries, specifically achieving high initial charge and discharge efficiency and low DC resistance in a low charged state.
Innovation Solution
A lithium metal composite oxide with a layered structure, containing Li, Ni, and an element X (such as Co, Mn, Fe, Cu, Ti, Mg, Al, W, Mo, Nb, Zn, Sn, Zr, Ga, B, Si, or P, where Ni/(Ni+X) is 0.7 or more, and a specific crystallite size distribution and particle size range, is used as a positive electrode active material. This composite oxide has a diffraction peak within a certain angle range and a relative standard deviation of crystallite size distribution between 0.20 and 0.55, and a tap density between 1.8 and 3.2 g/cc.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a lithium metal composite oxide with high Ni concentration is used to increase energy density, then the energy density is improved, but the control of crystallite size distribution becomes more difficult and performance consistency deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the Ni concentration ratio (Ni/(Ni+X) ≥ 0.7) and establishing specific ranges for crystallite size (100-500 nm) and relative standard deviation (0.15-0.40). This systematic parameter optimization resolves the contradiction by defining exact thresholds that simultaneously achieve high energy density through elevated Ni content while maintaining manufacturability through controlled crystallite size distribution
Solution Approach 2:
The patent applies local quality by specifying that the crystallite size distribution characteristics (100-500 nm range with RSD of 0.15-0.40) should be localized to particular regions or phases within the composite oxide structure. This allows different regions to have optimized properties: high Ni concentration zones for energy density while maintaining controlled crystallite dimensions for manufacturing consistency
2Productivity
If the crystallite size distribution is controlled to improve battery performance, then the charge and discharge efficiency is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent simplifies manufacturing complexity by establishing clear, measurable parameter ranges for crystallite size (100-500 nm) and relative standard deviation (0.15-0.40). These defined thresholds provide straightforward quality control criteria that can be monitored and adjusted during production, transforming a complex manufacturing challenge into a manageable parameter optimization task
Solution Approach 2:
The patent replaces complex mechanical control methods with characterization-based control using XRD analysis. By substituting direct mechanical manipulation of crystallite sizes with indirect control through synthesis parameter optimization and verification via diffraction patterns, the manufacturing process becomes less mechanically complex while maintaining precision in achieving the desired crystallite size distribution for high charge and discharge efficiency
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 lithium metal composite oxide enables lithium secondary batteries with high initial charge and discharge efficiency and low DC resistance in a low charged state, improving the battery's performance and cycle retention rate.
Implementation Method 1
a lithium secondary battery having a high initial charge and discharge efficiency
Implementation Method 2
in a powder X-ray diffraction measurement of the lithium metal composite oxide using CuKα rays, a diffraction peak is present within a range of a diffraction angle 2θ=18.7±1°
Data Source
AI summary
A lithium metal composite oxide having a layered structure, containing Li, Ni, and an element X, in which the element X is at least one element selected from the group consisting of Co, Mn, Fe, Cu, Ti, Mg, Al, W, Mo, Nb, Zn, Sn, Zr, Ga, B, Si, S, and P, Ni/(Ni+X), which is a ratio of the number of moles of Ni to the total number of moles of Ni and the element X, is 0.7 or more, and in a powder X-ray diffraction measurement of the lithium metal composite oxide using CuKα rays, a diffraction peak is present within a range of a diffraction angle 2θ=18.7±1°, and a relative standard deviation of a volume-based crystallite size distribution calculated from the diffraction peak within the range of 2θ=18.7±1° is 0.20 or more and 0.55 or less.