Lithium Composite Metal Oxide for Battery Cycle Performance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium secondary batteries require improved cycle performance for their positive electrode active materials to meet advancing application demands.
Innovation Solution
A lithium composite metal oxide is developed with specific characteristics, including a defined ratio of diffraction peak half widths, particle size distribution, and composition, which enhances the isotropic crystallinity and electrode density, leading to improved stability and charge/discharge efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the positive electrode active material uses conventional lithium composite metal oxide, then the battery can operate, but the cycle performance is insufficient for advancing application demands
Solution Approach 1:
The patent applies parameter changes by precisely controlling the ratio of half widths of diffraction peaks (A/B ratio between 1.39-1.75) and particle size distribution (D90/D10 ratio of 3 or more). These parameter specifications transform the conventional material into one with superior cycle performance, directly resolving the contradiction between reliability improvement and manufacturing precision requirements.
Solution Approach 2:
The patent uses composite materials by creating a lithium composite metal oxide with specific compositional ratios and structural characteristics. The material combines multiple elements in controlled proportions to achieve both high reliability (cycle performance) and meet manufacturing precision requirements through defined crystal structure parameters.
2Reliability
If the diffraction peak half width ratio is not controlled within 1.39-1.75, then manufacturing is easier, but cracks between crystallites form reducing cycle performance
Solution Approach 1:
The patent establishes specific parameter ranges (A/B ratio of 1.39-1.75) that prevent crack formation between crystallites. By defining this critical parameter range, the patent simultaneously improves reliability (prevents cracking) and provides clear manufacturing guidelines, transforming an ease-of-manufacture issue into a controlled parameter specification.
3Productivity
If the particle size distribution ratio D90/D10 is less than 3, then particle size control is simpler, but electrode density and charge/discharge efficiency are reduced
Solution Approach 1:
The patent specifies a particle size distribution parameter (D90/D10 ratio of 3 or more) that simultaneously improves productivity (charge/discharge efficiency) and provides clear manufacturing control criteria. This parameter specification resolves the contradiction by making the precision requirement quantitative and achievable.
4Stability of the object's composition
If the integral intensity ratio I2/I1 is not within 4.0-6.0, then manufacturing is simpler, but isotropic crystallinity is reduced affecting stability
Solution Approach 1:
The patent defines a specific parameter range (I2/I1 ratio of 4.0-6.0) that ensures isotropic crystallinity and compositional stability. This parameter specification transforms the stability requirement into a measurable and controllable manufacturing parameter, resolving the contradiction between stability improvement and manufacturing simplicity.
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 composite metal oxide achieves high cycle performance by minimizing cracks between crystallites and optimizing electrode density, resulting in enhanced maintenance of discharge capacity over repeated cycles.
Implementation Method 1
a ratio (A/B) of a half width A of a diffraction peak in a range of 2θ=64.5±1° with respect to a half width B of a diffraction peak in a range of 2θ=44.4±1° in a powder X-ray diffraction measurement for the lithium composite metal oxide using Cu-Kα ray
Data Source
AI summary
The present invention relates to a lithium composite metal oxide which satisfies the requirements (1) and (2) described below. Requirement (1): The ratio of the half width A of the diffraction peak within the range of 2θ=64.5±1° to the half width B of the diffraction peak within the range of 2θ=44.4±1°, namely A/B is from 1.39 to 1.75 (inclusive) in powder X-ray diffractometry using a Cu—Kα ray. Requirement (2): The ratio of the volume-based 90% cumulative particle size (D90) to the volume-based 10% cumulative particle size (D10), namely D90/D10 is 3 or more.