Battery-Grade Lithium Fluoride Production Without HF Handling
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Solution Overview
Problem
The production of lithium hexafluorophosphate (LiPF6) for lithium-ion batteries relies on hazardous hydrogen fluoride (HF), which poses handling challenges, limits shipping, and may not meet growing demand due to availability issues, necessitating a safer and more sustainable alternative for producing high-purity lithium fluoride (LiF).
Innovation Solution
A process utilizing fluorosilicic acid (FSA) as a by-product from HF manufacturing and fertilizer production to produce high-purity LiF, avoiding the use of HF, and enabling recycling of FSA to create a circular economy, with a flexible and safer production method that can be easily transported and scaled globally.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrogen fluoride (HF) is used as the starting material for producing lithium fluoride (LiF), then the production process is well-established and can achieve high purity LiF, but the process involves hazardous chemical handling, requires specific authorizations, and faces shipping and availability limitations
Solution Approach 1:
The invention extracts and removes the hazardous HF component from the production process by using fluorosilicic acid (H2SiF6) as an alternative starting material. This substitution eliminates the need to handle, ship, and store dangerous HF while maintaining the ability to produce high-purity LiF through the reaction: 2LiOH + H2SiF6 → 2LiF + SiO2 + 2H2O
Solution Approach 2:
The invention introduces fluorosilicic acid (H2SiF6) as an intermediary substance that serves as a safe alternative to HF. This intermediary provides the necessary fluorine source for LiF production without the hazardous properties of HF, and it can be easily transported and handled using standard chemical handling procedures
2Object-affected harmful factors
If fluorosilicic acid (H2SiF6) is used as an alternative to HF for producing LiF, then safety and transportability are improved, but the process must achieve comparable high purity standards (>99%) for battery grade applications
Solution Approach 1:
The invention controls the purity of LiF by adjusting reaction parameters including the concentration of H2SiF6 solution (5-50% w/w), reaction temperature (0-80°C), and the ratio of reactants. These parameter changes enable optimization of the reaction to produce battery-grade LiF with >99% purity while maintaining safety advantages
3Ease of manufacture
If traditional HF-based processes are used for LiF production, then the process is straightforward and well-known, but the availability of HF may not be sufficient to support growing demand from electric vehicle batteries and energy transition
Solution Approach 1:
The invention makes fluorosilicic acid (H2SiF6) a universal starting material that can be produced from multiple sources including phosphate fertilizer production and other industrial processes. This multi-functionality ensures adequate supply to meet growing demand from battery production while maintaining simple and efficient manufacturing processes
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 achieves a competitive yield of >90% highly pure LiF (>99% purity) suitable for LiPF6 production, reducing waste, energy consumption, and water usage, while addressing safety and scalability concerns, and allowing HF to be redirected to other applications.
Implementation Method 1
adding to said solution or suspension (iii) the solution of NH4F obtained in step (i) under stirring, to obtain a LiF precipitate
Implementation Method 2
to obtain a LiF precipitate
Data Source
AI summary
The present invention relates to a process for manufacturing a highly pure, battery grade, lithium fluoride (LiH) suitable for use as starting material in the production of lithium hexafluorophosphate (LiPF6) to be employed in the formulation of electrolytes solutions for the rechargeable electric battery market.