Lithium-Rich Cathode Material X-Ray Diffraction Optimization
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Solution Overview
Problem
Lithium ion secondary batteries using lithium-rich cathode active materials face challenges in achieving high discharge capacity and rate characteristics, particularly due to the high cost and limited effectiveness of cobalt-containing materials.
Innovation Solution
A cathode active material represented by aLi(Li1/3Mn2/3)O2·(1-a)LiMO2, where M is a transition metal element such as Ni, Co, or Mn, with specific ratios and structural characteristics that optimize the X-ray diffraction peak ratios and crystallite diameters, is used to enhance discharge capacity and rate characteristics without relying heavily on cobalt.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high Co proportion is used in cathode active material, then rate characteristics are improved, but manufacturing cost increases
Solution Approach 1:
The patent optimizes the crystal structure parameters by controlling the H020/H003 and H110/H003 ratios within specific ranges, which modifies the layered structure to improve Li ion diffusion pathways. This structural parameter optimization enables good rate characteristics without requiring high Co content, thus resolving the contradiction between performance and cost
Solution Approach 2:
The patent uses composite cathode active material containing multiple transition metals (Ni, Co, Mn) in specific proportions, combined with a specific layered structure (H020/H003 ≤ 0.038 and H110/H003 ≤ 0.013). This composite approach leverages the advantages of different metals while minimizing expensive Co content, achieving both good rate characteristics and cost effectiveness
2Quantity of substance
If lithium rich cathode active material is used, then discharge capacity is improved, but rate characteristics deteriorate
Solution Approach 1:
The patent changes the crystal structure parameters by controlling the H020/H003 and H110/H003 ratios, which modifies the layered structure to improve Li ion diffusion pathways. This structural optimization resolves the contradiction by enabling fast ion transport (good rate characteristics) while maintaining high lithium content (high discharge capacity)
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 proposed cathode active material achieves improved discharge capacity and rate characteristics in lithium ion secondary batteries, while reducing the reliance on costly cobalt, thereby lowering the overall battery cost and enhancing performance.
Implementation Method 1
in an X-ray diffraction pattern of the lithium-containing composite oxide, the ratio of the height (H020) of a peak of (020) plane assigned to a crystal structure with space group C2/m to the height (H003) of a peak of (003) plane assigned to a crystal structure with space group R-3m
Data Source
AI summary
A cathode active material for a positive electrode for a lithium ion secondary battery, comprising a lithium-containing composite oxide represented by aLi(Li1/3Mn2/3)O2·(1-a)LiMO2 (M: at least one transition metal element selected from Ni, Co and Mn, and 0<a<1), wherein in an X-ray diffraction pattern of the lithium-containing composite oxide, the ratio of the height (H020) of a peak of (020) plane assigned to a crystal structure with space group C2/m to the height (H003) of a peak of (003) plane assigned to a crystal structure with space group R-3m (i.e. H020/H003) is at most 0.038, and the ratio of the height (H110) of a peak of (110) plane assigned to a crystal structure with space group C2/m to the height (H003) of a peak of (003) plane assigned to a crystal structure with space group R-3m (i.e. H110/H003) is at most 0.013.