Lithium Metal Phosphate Dispersion for Stable Battery Coatings
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Solution Overview
Problem
Existing methods for preparing lithium metal phosphate coatings on battery electrodes result in unstable dispersions with large agglomerates and high viscosity, leading to non-homogeneous coatings unsuitable for lithium ion batteries.
Innovation Solution
A dispersion comprising 1-50% lithium metal phosphate of formula Li1+aM2−bNc(PO4)3+d, where M=Ti, Zr or Hf, and 50-99% trialkyl phosphate, prepared using a pyrogenic process, is stabilized with dynamic light scattering and milling to achieve fine particles and low viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If common solvents (alcohols or dimethoxyethane) are used to prepare lithium metal phosphate dispersions, then the dispersion can be initially formed, but it becomes unstable and forms large agglomerates with high viscosity
Solution Approach 1:
The patent changes the chemical parameter of the solvent from common alcohols or dimethoxyethane to trialkyl phosphates (such as trimethyl phosphate, triethyl phosphate, tri-n-propyl phosphate, tri-isopropyl phosphate, or a mixture thereof). This parameter change fundamentally alters the solvent's interaction with lithium metal phosphate particles, preventing agglomerate formation and maintaining low viscosity over time while preserving initial dispersion formation capability
2Ease of manufacture
If lithium metal phosphate coating is prepared directly on electrode surface using precursor solutions, then coating can be applied, but very careful selection of reaction conditions is required to ensure compatibility with precursors and substrate
Solution Approach 1:
The patent performs the coating material preparation in advance by creating a stable lithium metal phosphate dispersion in trialkyl phosphate solvent before application. This preliminary action separates the material preparation from the coating application process, allowing the dispersion to be pre-stabilized and stored without requiring careful control of reaction conditions during the actual coating process, thus simplifying the manufacturing procedure
Solution Approach 2:
The patent extracts the complex reaction condition control requirements from the coating application process by pre-forming the stable dispersion. The problematic aspects of precursor compatibility and reaction condition selection are removed from the actual coating step, leaving only the simple application of a pre-stabilized dispersion
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 dispersion provides stable, low-viscosity coatings that maintain particle stability for weeks, suitable for high-quality coatings on lithium ion battery components.
Implementation Method 1
preparation of such ready-to-use dispersions is quite problematic. Using common solvents, such as alcohols or dimethoxyethane (DME) lead to unstable dispersions, tending to formation of large agglomerates of lithium metal phosphate and highly viscous pastes instead of desired fine particulate dispersions.
Implementation Method 2
stabilized with dynamic light scattering and milling to achieve fine particles and low viscosity
Implementation Method 3
stabilized with dynamic light scattering and milling to achieve fine particles and low viscosity
Data Source
AI summary
A dispersion may include 1 to 50% by weight of lithium metal phosphate of a general formulaLi1+aM2−bNc(PO4)3+d,wherein M is Ti, Zr or Hf; N is a metal other than Li and M; 0≤a≤0.6, 0≤b≤0.6, 0≤c≤0.6, 0≤d≤0.8; and 50 to 99% by weight of trialkyl phosphate. A coating composition may include such a dispersion and such dispersions can be used in lithium ion batteries.