Lithium Difluorophosphate Synthesis Under Low-Moisture Reaction Control
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Solution Overview
Problem
Existing methods for producing lithium difluorophosphate suffer from low yield and impurities due to high moisture content in reaction systems, which affect the performance and cost-effectiveness of lithium secondary batteries.
Innovation Solution
A method involving controlled reactions in low-moisture organic solvents with specific molar ratios and temperature conditions to produce lithium difluorophosphate, using fluorine sources like HF and lithium sources like LiOH, to minimize impurity generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing methods are used to produce lithium difluorophosphate, then the production process is simple, but the yield is low and purity is poor due to high moisture content
Solution Approach 1:
The patent applies parameter changes by strictly controlling the moisture content of reactants (fluorine source, lithium source, oxygen source) to less than 1,000 ppm, and optimizing reaction parameters such as molar ratios (fluorine to phosphoryl halide: 1.75-3.5, lithium and oxygen to reaction product: 0.75-1.25) and temperature ranges (step S1: 15-35°C, step S2: 40-70°C). This precise parameter control eliminates moisture-related impurities while maintaining a feasible two-step production process.
Solution Approach 2:
The patent segments the production process into two distinct steps: Step S1 involves reacting fluorine source with phosphoryl halide in a first organic solvent to form an intermediate, and Step S2 involves reacting the intermediate with lithium source and oxygen source in a second organic solvent. This segmentation allows for optimized moisture control and reaction conditions in each step, achieving high purity without excessive overall complexity.
2Productivity
If existing methods are used to produce lithium difluorophosphate, then the production process is straightforward, but the yield is low due to moisture-related side reactions
Solution Approach 1:
The patent improves yield by changing the moisture parameter of all reactants to less than 1,000 ppm, which prevents moisture-related side reactions that consume reactants and reduce product formation. The optimized molar ratios and temperature parameters further enhance reaction efficiency and yield while maintaining reasonable manufacturing complexity.
3Manufacturing precision
If high moisture content reactants are used, then the production process is easier, but impurities increase and product quality deteriorates
Solution Approach 1:
The patent directly addresses this contradiction by changing the moisture content parameter of reactants from high (unspecified in prior art) to strictly controlled levels of less than 1,000 ppm. This parameter change eliminates moisture-related impurities such as phosphoric acid and lithium phosphate, achieving high product purity while the controlled nature of this single parameter change keeps the manufacturing process manageable.
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 achieves high yield and high purity of lithium difluorophosphate, reducing manufacturing costs and improving battery performance.
Implementation Method 1
reacting a fluorine source and a phosphoryl halide represented by Formula 1 below in a first organic solvent
Implementation Method 2
reacting the reaction product in step S1, a lithium source and an oxygen source in a second organic solvent
Data Source
AI summary
A method for producing lithium difluorophosphate includes reacting a fluorine source and a phosphoryl halide represented by Formula 1 in a first organic solvent to obtain a reaction product and reacting the reaction product, a lithium source, and an oxygen source in a second organic solvent. Each of the fluorine source, the lithium source and the oxygen source may have a moisture content of less than 1,000 ppm based on the weight thereof.