LiFSI Material Recovery Process for Fluoride and Solvent Reuse

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Solution Overview

Problem

The production of lithium bis(fluorosulfonyl)imide (LiFSI) is hindered by high costs due to cumbersome processes, low product conversion rates, large energy consumption, and environmental pollution, with challenges in recovering raw and auxiliary materials and removing water impurities.

Innovation Solution

A method involving multiple recovery sections for triethylamine, fluoride, ester solvent, and waste gas recovery, including alkalinization, evaporation, and dehydration processes to separate and purify these materials, achieving high-purity recovery and reuse.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If lithium fluoride and sulfur trioxide are used as raw materials to produce lithium bis(fluorosulfonyl)imide, then the production process is simple and energy consumption is low, but the recovery rate of lithium fluoride is low and sulfur trioxide is lost

Engineering Contradiction:
Improveproduction process simplicityVSAvoidlithium fluoride recovery rate
Core Design Contradiction:
Ease of manufactureVSLoss of substance

Solution Approach 1:

The patent implements a recovery system where spent electrolyte containing lithium fluoride is treated to recover and reuse lithium fluoride. The process includes filtering the spent electrolyte, adding calcium oxide to precipitate calcium fluoride, and then recovering lithium fluoride through acid treatment and purification, thereby converting waste into reusable raw material.

Inventive Principle:
Principle #34Discarding and recovering

Solution Approach 2:

The patent uses calcium oxide as an intermediary substance to facilitate the recovery of lithium fluoride. Calcium oxide reacts with hydrofluoric acid to form calcium fluoride precipitate, which then serves as an intermediate that can be converted back to lithium fluoride through further chemical treatment, enabling the recovery cycle.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If lithium fluoride and sulfur trioxide are used as raw materials, then production cost is reduced, but sulfur trioxide is lost and causes environmental pollution

Engineering Contradiction:
Improveproduction costVSAvoidsulfur trioxide pollution
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful loss of sulfur trioxide into a beneficial recovery process. By capturing and treating the sulfur-containing waste streams from electrolyte decomposition, the system recovers sulfur trioxide or sulfuric acid that can be reused, transforming an environmental hazard into a resource recovery opportunity.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Loss of substance

If conventional methods are used to recover lithium fluoride, then some recovery is achieved, but the production cost increases and the process becomes complex

Engineering Contradiction:
Improvelithium fluoride recoveryVSAvoidrecovery process complexity
Core Design Contradiction:
Loss of substanceVSDevice complexity

Solution Approach 1:

The patent merges the lithium fluoride recovery process with the existing production process. The recovery operations are integrated into the overall manufacturing workflow, combining multiple functions (filtration, chemical treatment, purification) into a unified process system that recovers materials without requiring entirely separate complex facilities.

Inventive Principle:
Principle #5Merging (Combining)

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 enhances the economic efficiency and environmental friendliness of LiFSI production by significantly improving the recovery and reuse of raw materials, reducing waste generation and production costs.

Implementation Method 1

adding calcium oxide to react with the hydrofluoric acid to generate calcium fluoride

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

electrolysis of lithium bis(fluorosulfonyl)imide

Methodology Applied
Scientific EffectElectrolysis: Electrolysis

Data Source

PatentEP4273100B1Method for recovering raw and auxiliary materials in production of lithium bis(fluorosulfonyl)imide
Publication Date: 2026.04.29 CONTEMPORARY AMPEREX TECHNOLOGY CO LTD
  • EP4273100B1 patent drawingFigure 1~2
  • EP4273100B1 patent drawingFigure 3~5
  • EP4273100B1 patent drawingFigure 6~7

AI summary

The present application relates to a method for recovering raw and auxiliary materials in the production of lithium bis(fluorosulfonyl)imide. The method includes one or more different recovery sections A, B, C, D and/or E, corresponding to the recovery and post-treatment of the raw and auxiliary materials such as triethylamine, a fluoride ion, an ester solvent, and a crystallization liquid respectively used in the production of lithium bis(fluorosulfonyl)imide. The method for recovering raw and auxiliary materials of the present application enables the production of lithium bis(fluorosulfonyl)imide to have significantly improved economic efficiency and environmental protection.