Li-Ion Battery Electrolyte Recycling via Solvent Extraction
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Solution Overview
Problem
Current methods for recycling lithium-ion battery electrolytes fail to effectively isolate lithium salts and organic solvents while avoiding the degradation of lithium hexafluorophosphate anions, which generates toxic substances and hampers the recycling process.
Innovation Solution
A process involving the treatment of the battery electrolyte with water and an organic addition solvent, followed by filtration and distillation to separate aqueous and organic phases, with the anion of the lithium salt being precipitated and reused to re-synthesize lithium hexafluorophosphate, using pyridine and carbonate/phosphate salts to recover lithium salts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If thermal processes are used to recycle Li-ion batteries, then energy consumption is reduced and processing speed is improved, but toxic gases and fine particles are generated that harm the environment and human health
Solution Approach 1:
The patent employs an inert atmosphere (nitrogen or argon) throughout the recycling process to prevent oxidation reactions. The battery is ground, extracted, and processed in an inert environment, which eliminates the generation of toxic gases and fine particles while maintaining high processing efficiency. This resolves the contradiction by providing a clean processing environment that protects both productivity and environmental safety.
Solution Approach 2:
The patent converts the potentially harmful thermal decomposition process into a beneficial cold extraction process. Instead of using heat that generates toxic emissions, the invention uses solvent extraction at ambient or controlled temperatures to recover electrolyte components, transforming a harmful thermal process into a clean, environmentally friendly operation that maintains productivity.
2Manufacturing precision
If phosphonium chloride is used to extract electrolyte from battery, then lithium salt separation is achieved, but impurities are generated in both liquid and solid phases requiring additional purification
Solution Approach 1:
The patent uses a different extraction approach that selectively removes electrolyte components without generating impurities. The extraction process targets specific substances for removal while leaving the battery components clean, eliminating the need for complex purification steps. This resolves the contradiction by achieving separation precision through selective extraction rather than precipitation methods that contaminate both phases.
Solution Approach 2:
The patent introduces a carefully selected solvent as an intermediary that facilitates selective extraction without creating impurities. The solvent acts as a mediator that binds to target electrolyte components for removal while being easily separable and non-contaminating, thus achieving precise lithium salt separation without complicating the purification process.
3Manufacturing precision
If fractional distillation is used to separate electrolyte components, then organic solvents and lithium salt are separated, but the hexafluorophosphate anion degrades generating toxic substances
Solution Approach 1:
The patent changes the operating parameters from high-temperature fractional distillation to low-temperature solvent extraction. By operating at ambient or controlled low temperatures, the process achieves effective separation of electrolyte components without providing the thermal energy needed for hexafluorophosphate anion degradation, thus eliminating toxic substance generation while maintaining separation precision.
Solution Approach 2:
The patent replaces the thermal-mechanical separation system (fractional distillation) with a chemical-selective extraction system. Instead of using heat and temperature gradients to separate components, the invention uses selective solvent interactions to achieve separation at low temperatures, preventing anion degradation and toxic emissions while maintaining effective component separation.
4Productivity
If battery materials are focused on high added value elements like cobalt and nickel, then economic recovery is improved, but electrolyte recovery is neglected despite regulatory constraints
Solution Approach 1:
The patent segments the battery recycling process into distinct stages: high-value material recovery (cobalt, nickel) followed by dedicated electrolyte recovery. This segmentation allows the process to first address economic priorities through metal recovery, then systematically treat the electrolyte component to meet regulatory requirements, thus resolving the contradiction between economic efficiency and regulatory compliance.
Solution Approach 2:
The patent performs preliminary separation of the electrolyte from solid battery components before the main recycling process. This preliminary action isolates the electrolyte for dedicated treatment, ensuring that both high-value metal recovery and electrolyte recovery (for regulatory compliance) are achieved systematically without compromising either economic efficiency or environmental standards.
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 allows for the efficient recycling of lithium salts and organic solvents, preventing the degradation of lithium hexafluorophosphate anions and enabling their reuse, thus enhancing the recycling efficiency and safety of lithium-ion battery electrolytes.
Implementation Method 1
A process involving the treatment of the battery electrolyte with water and an organic addition solvent, followed by filtration and distillation to separate aqueous and organic phases
Implementation Method 2
followed by filtration and distillation to separate aqueous and organic phases
Implementation Method 3
with the anion of the lithium salt being precipitated and reused to re-synthesize lithium hexafluorophosphate, using pyridine and carbonate/phosphate salts to recover lithium salts
Data Source
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AI summary
The invention relates to a method for recycling the electrolyte of a lithium-ion battery and a method for recycling lithium-ion batteries. The method for recycling an electrolyte of the invention is a method for recycling an electrolyte containing a lithium salt of formula LiA, where A represents an anion selected from PF6, CF3SO3, BF4, ClO4 and [(CF3SO2)2]N of a Li-ion battery, characterized in that it comprises the following steps: a) optionally, treatment of the battery in order to recover the electrolyte that it contains; b) addition of water to the electrolyte; c) optionally, when step a) is carried out, filtration (F1) in order to separate the liquid phase containing the electrolyte from the solid phase comprising the residues of the battery; d) addition of an additional organic solvent to the liquid phase obtained in step b) or, when step a) is carried out, after the filtration (F1) of step c); e) decantation of the liquid phase obtained after step b) of adding water or step d) of adding additional organic solvent, whereby an aqueous phase containing the lithium salt and an organic phase containing the electrolyte solvents and the additional organic solvent are obtained; f) distillation of the organic phase obtained in step e) in order to separate the solvents of the electrolyte and the additional organic solvent; g) precipitation of the anion A of the lithium salt by addition of pyridine followed by filtration (F2); h) addition of at least one carbonate salt and/or of at least one phosphate salt to the filtrate obtained in step g) followed by filtration (F3) whereby a lithium salt and water are obtained. The invention finds its application in the field of recycling lithium-ion batteries, and more particularly the electrolyte of such batteries.