Lithium Composite Oxide Crystallite Control for Battery Cycle Stability
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Solution Overview
Problem
Lithium ion secondary batteries face challenges in maintaining discharge capacity and cycle characteristics due to cation mixing in the crystal structure of lithium-containing composite oxides, which affects both cycle and rate characteristics.
Innovation Solution
A production method for lithium-containing composite oxides is developed, focusing on controlling the peak intensity ratio (I003/I104) and crystallite diameter of the (110) plane, using a transition metal hydroxide with a crystallite size of 35 nm or less in the space group P-3m1, and incorporating a lithium source, to suppress cation mixing and enhance crystal structure stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the crystallite size of the (110) plane is increased to improve structural stability, then the cycle characteristics decrease
Solution Approach 1:
The patent applies parameter changes by precisely controlling the crystallite size of the (110) plane to 100 nm or less and the (100) plane to 35 nm or less. These specific size parameters prevent cation mixing while maintaining structural stability, thereby improving cycle characteristics without sacrificing structural integrity
Solution Approach 2:
The patent employs preliminary action by controlling the crystallite size of the starting transition metal hydroxide before the lithium-containing composite oxide formation process. By pre-establishing the appropriate crystallite size in the hydroxide precursor, the final oxide achieves optimal structure that prevents cation mixing and ensures excellent cycle characteristics
2Quantity of substance
If cation mixing occurs in the crystal structure, then the discharge capacity increases initially, but the path for lithium ion diffusion is blocked and cycle characteristics decrease
Solution Approach 1:
The patent applies preliminary anti-action by implementing preventive measures against cation mixing through strict control of crystallite sizes. By maintaining the (110) plane at 100 nm or less and the (100) plane at 35 nm or less, the structure inherently resists cation mixing, preserving lithium ion diffusion paths and ensuring long-term cycle stability
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 method results in improved cycle and rate characteristics of lithium ion secondary batteries by reducing cation mixing and maintaining discharge capacity, with the lithium-containing composite oxide exhibiting a peak intensity ratio of 1.18 to 1.35 and a crystallite diameter of 73 nm or less, leading to enhanced battery performance.
Implementation Method 1
a transition metal hydroxide having a crystallite size of the (100) plane being 35 nm or less in a crystal structure model in the space group P-3m1 of an X-ray diffraction pattern is used
Implementation Method 2
when producing a lithium-containing composite oxide by mixing a transition metal hydroxide containing Ni and Mn essentially and a lithium source and heating the mixture
Implementation Method 3
in an X-ray diffraction pattern of the lithium-containing composite oxide, an integral value (I003) of a diffraction peak of the (003) plane and an integral value (I104) of a diffraction peak of the (104) plane
Data Source
AI summary
There is provided a production method of a lithium-containing composite oxide capable of improving performances of cycle characteristics, rate characteristics, and the like of a lithium ion secondary battery. A production method of a lithium-containing composite oxide is characterized in that when producing a lithium-containing composite oxide by mixing a transition metal hydroxide containing Ni and Mn essentially and a lithium source and heating the mixture, a transition metal hydroxide having a crystallite diameter of the (100) plane being 35 nm or less in a crystal structure model in the space group P-3m1 of an X-ray diffraction pattern is used.