Aqueous TEMPO Electrolyte Production for Scalable Redox-Flow Cells
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Solution Overview
Problem
Existing production processes for redox-flow cells using TEMPO-derivatives are complex, require multiple solvents, and result in high losses and costs, making them unsuitable for industrial scale, while current aqueous solutions lack flexibility in anion choice and require base addition.
Innovation Solution
A process involving the reaction of N,N,2,2,6,6-hexamethyl-4-piperidinamine with dimethyl carbonate in a saturated C1 to C4 alcohol, followed by solvent change to water, oxidation with hydrogen peroxide, and pH adjustment, results in an aqueous solution of TEMPO-derivatives with controlled composition and properties suitable for redox-flow cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing production processes for TEMPO-derivatives are used, then pure compounds are obtained, but the process complexity increases and industrial scalability decreases
Solution Approach 1:
The invention extracts and eliminates the problematic intermediate solid separation steps from the production process. By using a continuous aqueous phase process without solid intermediate compounds, the method removes the need for filtration and centrifugation steps, thereby reducing process complexity while maintaining product purity.
Solution Approach 2:
The invention changes the physical state parameters of the reaction system by using aqueous solutions throughout the process instead of organic solvents that form solid intermediates. This parameter change from solid-liquid to liquid-liquid system eliminates the need for solid handling and separation operations, simplifying the overall process.
2Quantity of substance
If existing production processes with multiple solvents are used, then TEMPO-derivatives are produced, but solvent recycling becomes complicated and costs increase
Solution Approach 1:
The invention uses water as a universal solvent that serves multiple functions throughout the entire production process - as reaction medium, product solvent, and electrolyte component. This eliminates the need for multiple different solvents and their associated recycling processes, simplifying manufacturing while maintaining production efficiency.
Solution Approach 2:
The invention creates a homogeneous aqueous reaction system where all steps occur in the water phase, eliminating the need for solvent changes and complex recycling operations. The uniform aqueous environment simplifies both production and subsequent handling of the TEMPO-derivative.
3Productivity
If base addition is used during oxidation step, then oxidation proceeds efficiently, but additional salts are formed requiring removal
Solution Approach 1:
The invention employs an auto-catalytic oxidation mechanism where the reaction itself generates the necessary conditions for continued oxidation without requiring external base addition. The hydroperoxide intermediate formed during oxidation self-regulates the pH, eliminating the need for additional base and preventing salt formation that would require removal.
Solution Approach 2:
The invention converts the typically harmful effect of pH change during oxidation into a beneficial self-regulating feature. The pH decrease during oxidation is not countered by base addition but is instead utilized as part of the reaction mechanism, with the pH naturally returning to optimal levels as the reaction progresses, eliminating salt waste.
4Manufacturing precision
If filtration and centrifugation steps are used, then solid intermediates are separated, but time loss and yield reduction occur
Solution Approach 1:
The invention extracts and eliminates the solid intermediate formation entirely from the reaction pathway by using a continuous aqueous phase process. Without solid intermediates, there is no need for filtration or centrifugation steps, thereby eliminating the associated time losses and yield reductions from these separation operations.
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 process enables an efficient, low-cost production of an aqueous solution with controlled anion composition, suitable for industrial scale, maintaining energy storage properties comparable to state-of-the-art solutions without additional base addition.
Implementation Method 1
oxidation with hydrogen peroxide
Implementation Method 2
redox-flow cells with new organic compounds as redox couple comprising 2,2,6,6-tetramethylpiperidinyl-oxyl (TEMPO)-derivates
Data Source
AI summary
The present invention relates to a solution comprising water and different 2,2,6,6-tetramethyl-piperidinyl-oxyl (TEMPO)-derivatives, a process for the production of this solution, a process for making a redox-flow cell comprising the solution as electrolyte, a redox-flow cell comprising the solution as an electrolyte in one chamber of the cell and the use of the redox-flow cell for storing electrical energy.