Lithium Phosphorus Oxide Powder via Glass-Ceramic Precursor Crystallization
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Solution Overview
Problem
Current methods for producing lithium phosphorus complex oxide powders for solid electrolyte materials in lithium ion batteries face challenges such as contamination, strain in crystal structures, and difficulty in achieving uniform particle sizes due to physical milling, and existing techniques using ZnO can result in impurities.
Innovation Solution
A method involving the production of a precursor glass with a specific lithium to phosphorus molar ratio, followed by heat treatment to form precursor crystallized glass, and subsequent acid treatment to elute lithium pyrophosphate, resulting in a high-quality lithium phosphorus complex oxide powder with reduced impurities and uniform particle distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If physical milling is used to obtain fine powder, then particle size is reduced, but contaminants are included and strain is generated in crystal structure
Solution Approach 1:
The patent applies preliminary action by forming a glass-ceramic precursor that already contains the desired crystal phases before final processing. The glass matrix is prepared in advance with controlled composition (Li2O: 30-70 mol%, P2O5: 10-40 mol%, Al2O3: 5-20 mol%, TiO2: 5-20 mol%) to prevent unwanted crystallization during subsequent steps, eliminating the need for aggressive milling that causes contamination and strain.
Solution Approach 2:
The patent replaces mechanical milling with a chemical/thermal approach. Instead of using mechanical force to reduce particle size, the invention uses controlled heat treatment of the glass-ceramic precursor to in-situ form fine crystal particles within the glass matrix, followed by gentle separation. This substitutes mechanical action with thermal and chemical processes that avoid introducing contaminants and crystal strain.
2Manufacturing precision
If high-level techniques and expensive equipment are used for physical milling, then sharp particle diameter distribution is achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent achieves sharp particle diameter distribution by controlling chemical composition parameters rather than mechanical processing parameters. The glass-ceramic precursor is formulated with specific ranges of Li2O (30-70 mol%), P2O5 (10-40 mol%), Al2O3 (5-20 mol%), and TiO2 (5-20 mol%) to control crystallization behavior. Heat treatment temperature and time are also controlled to achieve uniform crystal size without requiring complex milling equipment.
3Stability of the object's composition
If glass with low stability against devitrification is used, then crystal precipitation occurs at glass production, but crystal particle diameter becomes extremely large and uniform fineness cannot be obtained
Solution Approach 1:
The patent resolves this contradiction by optimizing the chemical composition parameters of the glass. The glass-ceramic precursor contains Li2O (30-70 mol%), P2O5 (10-40 mol%), Al2O3 (5-20 mol%), and TiO2 (5-20 mol%), which provides adequate stability against spontaneous devitrification during production. This controlled stability allows the glass to be formed first, then undergoes controlled crystallization during heat treatment to produce fine, uniform crystal particles rather than large irregular crystals.
Solution Approach 2:
The patent applies preliminary action by first forming the glass-ceramic precursor with controlled composition and structure, then performing controlled heat treatment to induce uniform crystal precipitation. This two-stage approach (glass formation followed by controlled crystallization) prevents premature or uncontrolled crystal growth, ensuring fine and uniform particle size distribution that would not be achievable with unstable glass compositions.
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
This method enables the production of high-quality lithium phosphorus complex oxide powders with reduced impurities and improved particle uniformity, addressing the limitations of existing techniques and enhancing the quality and consistency of the final product.
Implementation Method 1
heating a precursor glass and precipitating crystals of a lithium phosphorus complex oxide and crystals of lithium pyrophosphate
Implementation Method 2
acid treating a precursor crystallized glass to elute lithium pyrophosphate
Data Source
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AI summary
Provided is a high-quality lithium phosphorus complex oxide powder. The lithium phosphorus complex oxide powder comprises Li1+xMIIIxMIV2-x(PO4)3 (0 ≤ x ≤ 1, MIII represents an element selected from Al, Sc, Cr, Fe, Ga, and In, and MIV represents an element selected from Si, Ti, Ge, and Zr) and has a concentration of Zn as an impurity of less than 100 ppm.