Borate Salt Preparation via Organic Solvent Drying

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Solution Overview

Problem

Current methods for preparing and purifying salt compositions comprising multiple borate anions, such as those used in solid-state electrolytes, face challenges like contamination, unwanted side products, and difficulty in retaining stoichiometry and structure, especially when using mechano-chemical processes or solvents like water, which lead to impurities and inferior properties.

Innovation Solution

A method involving the mixing and drying of borate anions in specific solvents like C2-C6 alcohols, acetonitrile, and DMF, followed by solvent removal to produce a solid salt composition with retained stoichiometry and purity, avoiding incorporation of solvent molecules and mechanical milling debris.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If water is used as solvent for dissolving borate anions, then solubility is improved, but residual solvent molecules are incorporated into the solid salt composition leading to inferior properties

Engineering Contradiction:
Improvesolubility of borate anionsVSAvoidpurity of solid salt composition
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent changes the solvent parameter from water to organic solvents (alcohols, ethers, esters, nitriles, ketones, sulfones, carbonates). This parameter change allows the borate anions to dissolve in the organic solvent and then be recovered as completely anhydrous solids after solvent removal, eliminating water incorporation into the crystal lattice while maintaining high solubility during the dissolution step.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If mechano-chemical processes are used for preparing salt compositions, then mixing is achieved, but contamination and mechanical milling debris are introduced

Engineering Contradiction:
Improvemixing capabilityVSAvoidpurity of salt composition
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical milling system with a chemical dissolution system. Instead of using mechanical energy to force mixing of solid particles, the invention uses chemical solvents to dissolve the borate anions, creating a homogeneous solution that can then be dried to yield a pure mixed-anion salt composition without any mechanical debris or contamination.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Quantity of substance

If attempts are made to form solid solutions of multiple borate anions through drying, then salt composition is obtained, but stoichiometry and structure are disrupted

Engineering Contradiction:
Improveformation of salt compositionVSAvoidretention of stoichiometry and structure
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent performs preliminary mixing at the molecular level by dissolving the borate anions in a common organic solvent before drying. This preliminary action ensures that the anions are uniformly distributed in the solution phase, and upon drying, the mixed-anion salt crystallizes with the correct stoichiometry and intact structure, avoiding the disruption that occurs when attempting to form solid solutions directly from dry powders.

Inventive Principle:
Principle #10Preliminary action

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 produces pure, phase-pure salt compositions with retained stoichiometry and structure, suitable for use in solid-state electrolytes, achieving high purity and single-phase materials without the drawbacks of mechanical milling.

Implementation Method 1

mixing and/or dissolving the anions in a solvent selected from the group consisting of C 2 -C 6 alcohols; acetonitrile; ketone-comprising solvents, glymes, organic carbonates, ethers, C 2 -C 6 thiols, DMF, DMSO and thioethers

Methodology Applied
Scientific EffectSolvation: Solvation

Implementation Method 2

drying the solution of step (b) to obtain a solid salt composition comprising the at least two different borate anions

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3877334B1Method for the preparation and purification of borate salts
Publication Date: 2023.01.18 EIDGENISSISCHE MATERIALPRUFUNGS- UND FORSCHUNGSANSTALT EMPA
  • EP3877334B1 patent drawingFigure 1~2
  • EP3877334B1 patent drawingFigure 3~4
  • EP3877334B1 patent drawingFigure 5~6

AI summary

The present invention is directed to a method for the preparation and/or purification of a salt composition comprising at least two different borate anions, comprising the steps: (a) providing at least two different borate anions; (b) mixing and/or dissolving the anions in a solvent selected from the group consisting of C2-C6 alcohols; acetonitrile; ketone-comprising solvents, glymes, organic carbonates, ethers, C2-C6 thiols, DMF, DMSO and thioethers; and (c) drying the solution of step (b) to obtain a solid salt composition comprising the at least two different borate anions, optionally in the predetermined molar ratio. The invention is also directed to corresponding use of the method for the manufacture of a salt composition comprising at least two different borate anions, as well as to related products.