Ionic Liquid Electrolyte for Metal Deposition

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Solution Overview

Problem

Conventional metal deposition methods, such as iron deposition, face issues with hydrogen gas evolution, substrate brittleness, narrow stability windows, and contamination due to caustic aqueous solutions, leading to poor deposit quality and limited operating temperatures.

Innovation Solution

The use of a composition comprising a carboxamide, trialkylamine chloride, and a metal salt in an ionic liquid electrolyte, which induces a potential between a metal salt and a substrate to form a metal-metal bond, controlling grain size and minimizing impurities like oxygen, carbon, and chlorine in the deposit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional caustic aqueous solutions are used for metal deposition, then the deposition process can proceed, but hydrogen gas evolves causing substrate pitting and deposit brittleness

Engineering Contradiction:

Improvedeposition processVSAvoidhydrogen gas evolution

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent changes the fundamental parameter of the electrolyte from aqueous to ionic liquid, which has a much wider electrochemical stability window and does not produce hydrogen gas evolution, thereby eliminating the harmful effect while maintaining the deposition process

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The ionic liquid creates an inert electrochemical environment that prevents hydrogen evolution and substrate pitting, providing a protective deposition atmosphere that eliminates the harmful hydrogen gas effect

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

2Ease of manufacture

If conventional aqueous electrolytes are used, then deposition can occur, but the stability window is narrow at only 1.2 V

Engineering Contradiction:

Improvedeposition processVSAvoidstability window

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent changes the electrolyte composition from water-based to ionic liquid, fundamentally altering the electrochemical stability parameter from 1.2 V to over 3 V, enabling wider operating conditions and improved adaptability

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If higher temperatures are used to drive off hydrogen, then hydrogen removal improves, but crystal grain sizes become unfavorably large

Engineering Contradiction:

Improvehydrogen removalVSAvoidgrain size control

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent converts the harmful hydrogen evolution issue into a non-problem by using ionic liquid that does not produce hydrogen, thereby eliminating the need for high temperature treatment that would otherwise cause grain growth

Inventive Principle:

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

Solution Approach 2:

The ionic liquid electrolyte changes the electrochemical parameters to allow deposition at lower temperatures, which maintains fine grain structure while eliminating hydrogen evolution through a different mechanism

Inventive Principle:

Principle #35Parameter changes

4Ease of manufacture

If conventional aqueous deposition is used, then Fe3+ forms at the anode, but deposit quality is compromised when Fe3+ migrates to the cathode

Engineering Contradiction:

Improvedeposition processVSAvoiddeposit quality

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the electrolyte chemistry from aqueous to ionic liquid, which alters the speciation and migration behavior of metal ions, preventing Fe3+ contamination of the deposit while maintaining efficient deposition

Inventive Principle:

Principle #35Parameter changes

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 dense, pure metal deposits with controlled grain size and improved stability, avoiding hydrogen evolution and substrate contamination, and operates within a wider voltage and temperature range compared to conventional methods.

Implementation Method 1

inducing a potential between a metal salt and a substrate through an electrolyte to form a metal-metal bond

Methodology Applied

Scientific EffectElectrolysis: Electrolysis

Implementation Method 2

metal deposition, such as iron deposition, relies upon caustic aqueous solutions

Methodology Applied

Scientific EffectElectrochemical deposition: Electrodeposition

Data Source

PatentUS11274374B2Metal deposits, compositions, and methods for making the same

Publication Date: 2022.03.15 IONTRA INC

AI summary

Provided herein is a composition for forming a metal deposit on a substrate. The composition consists essentially of a carboxamide, trialkylamine chloride, and a metal salt. The carboxamide comprises Formula (I). The trialkylamine chloride and the carboxamide are in molar ratio between 1:1 and 1:30 to form an ionic liquid. The trialkylamine chloride is trimethylamine chloride (TMACl), triethylamine chloride (TEACl), triethanolamine chloride, or combinations thereof. The metal salt has the formula MXy, wherein M is a metal, X is a halide, and y is an oxidation number of M, the metal salt being in a concentration between about 0.2 and about 1.5 moles per liter of the ionic liquid. The metal deposit has an average grain size between about 0.2 μm and about 3 μm and contains less than about 1 mol % of each oxygen, carbon, and chlorine.