LiFSI Preparation Process for High Purity and Low Moisture
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Solution Overview
Problem
The industrial-scale production of lithium bis(fluorosulfonyl)imide (LiFSI) faces challenges such as low product purity, high moisture content, high production costs, and excessive waste generation due to cumbersome and inefficient synthesis processes.
Innovation Solution
A continuous method involving steps like reaction of sulfuryl fluoride, ammonia gas, and triethylamine, followed by evaporation, extraction, alkalinization, dehydration, and desolventization, with recycling of solvents and by-products, to produce high-purity LiFSI with reduced water content and lower production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional batch synthesis method is used for LiFSI production, then the process is simple to operate, but the production time is long and productivity is low
Solution Approach 1:
The patent implements continuous flow synthesis where reactants are continuously fed into the reaction system, undergo reaction in a flow reactor, and are continuously processed through extraction and purification stages. This continuous operation eliminates batch-to-batch interruptions, significantly reducing production time while maintaining process control through standardized flow conditions and residence times.
Solution Approach 2:
The synthesis process is divided into distinct modular stages: reaction zone, extraction zone, and purification zone. Each stage is optimized independently with specific parameters (temperature, pressure, flow rate) controlled for that segment. This segmentation allows parallel processing and continuous operation while maintaining operational simplicity through standardized modular units.
2Manufacturing precision
If traditional synthesis process is used, then the process is short and simple, but the product purity is low and moisture content is high
Solution Approach 1:
The patent incorporates an extraction stage where the reaction mixture is contacted with an extracting agent to separate and remove impurities and by-products from the desired LiFSI product. This extraction step effectively isolates the pure product while eliminating contaminants that would otherwise require complex multi-step purification sequences.
Solution Approach 2:
The process utilizes controlled parameter changes including temperature gradients, pressure variations, and solvent composition adjustments across different stages to optimize product purity. By carefully controlling reaction temperature, extraction solvent ratios, and evaporation conditions, the system achieves high purity LiFSI with low moisture content through a streamlined process.
3Ease of manufacture
If conventional production method is used, then the raw material consumption is low, but the production cost is high due to material loss and waste treatment
Solution Approach 1:
The patent implements recovery systems where solvents, catalysts, and unreacted materials are captured from waste streams and regenerated for reuse in the production process. This recovery approach minimizes raw material loss, reduces waste disposal requirements, and lowers overall production costs by eliminating the need for continuous fresh material input.
Solution Approach 2:
The process incorporates feedback loops where product quality and composition are continuously monitored, and process parameters are automatically adjusted to optimize yield and minimize waste. This closed-loop control ensures maximum raw material utilization while maintaining product specifications, reducing both material loss and associated treatment costs.
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-purity LiFSI with low moisture and reduced waste, lowering production costs and making the process suitable for industrial production by optimizing raw material utilization and recycling.
Implementation Method 1
subjecting sulfuryl fluoride, ammonia gas and triethylamine to reaction in a reaction device in the presence of a solvent to obtain a stream α1 containing (SO2F—NH—SO2F)·Et3N, a triethylamine hydrogen fluoride salt and triethylamine
Implementation Method 2
performing evaporation on the stream α1 to obtain a stream α2 containing (SO2F—NH—SO2F)·Et3N and the triethylamine hydrogen fluoride salt
Implementation Method 3
washing the stream α2 obtained in step (b) with water in an extraction tower or a static mixer to obtain an oil phaseα3 containing (SO2F—NH—SO2F)·Et3N and an aqueous phase αwater containing the triethylamine hydrogen fluoride salt
Implementation Method 4
performing reduced-pressure evaporation on the stream β1-1 to obtain a stream β1-2 containing lithium bis(fluorosulfonyl)imide
Implementation Method 5
delivering a filtrate g-1 obtained to a dehydration kettle containing a molecular sieve to remove water
Data Source
AI summary
A method for preparing lithium bis(fluorosulfonyl)imide includes a synthesis step, an evaporation step, an extraction step, an alkalinization step, a dehydration step, and a desolventization step.