High-Solids Catalyst Ink for CMR-Free Doctor Blade Coating
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Solution Overview
Problem
Existing catalyst inks for alkaline membrane water electrolysis (AEMWE) contain carcinogenic, mutagenic, or toxic solvents, leading to high production costs and poor doctorability, limiting the efficiency of electrochemical reactions.
Innovation Solution
A catalyst ink with a solvent mixture of acetonitrile and an alkanol, along with a binder of specific structures, is developed, allowing for high solids content and improved doctorability without using CMR substances, using additives like DMSO and water for viscosity adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional solvents (DMF, DMAc, DMSO) are used in catalyst ink, then the binder dissolves well and coating can be achieved, but the ink contains CMR substances leading to high production costs and safety concerns
Solution Approach 1:
The patent extracts and removes the harmful CMR substances (DMF, DMAc, DMSO) from the catalyst ink formulation while retaining the essential functionality of binder dissolution and coating formation through alternative solvent systems
Solution Approach 2:
The patent replaces expensive and hazardous traditional solvents with cheaper, safer alternatives (alcohols, water, esters) that can be easily handled and disposed of, reducing both production costs and safety risks
2Productivity
If high solids content is achieved in catalyst ink, then catalyst loading increases and productivity improves, but the ink viscosity increases making doctorability difficult
Solution Approach 1:
The patent changes the chemical composition parameters of the solvent system (using specific ratios of alcohols, water, and esters) to optimize the balance between solids content and viscosity, enabling high catalyst loading while maintaining good doctorability
Solution Approach 2:
The patent creates a composite solvent system combining multiple components (alcohols like ethanol/propanol, water, and esters like ethyl acetate) that work synergistically to provide both high solids content compatibility and appropriate rheological properties for coating
3Object-affected harmful factors
If CMR-free solvent systems are used, then production costs decrease and safety improves, but achieving high solids content with good coating quality becomes more difficult
Solution Approach 1:
The patent introduces intermediary substances (alcohols, esters, and water) that mediate between the binder and electrocatalyst, enabling proper dissolution and dispersion while maintaining CMR-free formulation and achieving high coating quality
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 ink achieves a homogeneous, high-quality coating with increased catalyst loading, enhancing the efficiency of alkaline water electrolysis by reducing power consumption and production costs.
Implementation Method 1
a liquid solvent mixture containing at least acetonitrile and at least one alkanol... a binder dissolved in the solvent mixture
Implementation Method 2
Once applied, the catalyst ink is dried so that the solvent evaporates and the binder precipitates from the solution
Implementation Method 3
the binder precipitates from the solution. What remains is the electrocatalyst and the binder, which together form the catalytically active or activatable coating
Data Source
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AI summary
The invention relates to a catalyst ink, a process for coating substrates with this ink, the coated substrates obtained by the process, and their use. The objective was to provide a catalyst ink that has a high solids content and, at the same time, is easy to doctor. The catalyst ink should, if possible, contain no solvents known to be carcinogenic, mutagenic, or toxic to reproduction. The coated substrates produced with the catalyst ink should be usable, in particular, in alkaline membrane water electrolysis as catalytically active or activatable anion exchange membranes. This objective was achieved by a solvent mixture containing alkanol and acetonitrile. The improvement lies in the fact that both the weight fraction of acetonitrile and the weight fraction of alkanol are greater than the weight fraction of the binder contained in the catalyst ink.