Organic Redox Flow Battery Electrolytes Beyond Solubility Limits
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Solution Overview
Problem
Redox flow batteries face limitations in energy density due to solubility constraints of redox species and reliance on scarce metal-based raw materials, which restrict their suitability for high-energy applications and increase production costs.
Innovation Solution
Development of metal-free, multi-component, low-transition temperature materials comprising a redox-active phase and an ionically conducting organic salt, allowing for higher mole fractions of redox-active components and enabling solvent-free operation with enhanced energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If metal-based redox species are used in redox flow batteries, then electrochemical energy storage is achieved, but energy density is limited due to solubility constraints and reliance on scarce raw materials
Solution Approach 1:
The patent changes the chemical composition parameters from metal-based redox species to organic redox-active compounds. This parameter change enables higher concentration of redox-active species in the electrolyte, achieving energy densities greater than 100 Wh/L while using abundant organic materials instead of scarce metals like vanadium, lithium, or cobalt
Solution Approach 2:
The patent employs composite electrolyte formulations combining redox-active organic compounds with supporting electrolytes and solvents. This composite approach enables optimization of both energy density and material availability, creating a new class of organic redox flow batteries that overcome the limitations of single-component metal-based systems
2Quantity of substance
If the concentration of redox-active phase is increased to improve energy density, then energy storage capacity increases, but solubility limitations are encountered
Solution Approach 1:
The patent changes the chemical nature of the redox-active species from metal-based to organic compounds with tailored molecular structures. This enables higher solubility and stability at elevated concentrations, allowing energy densities exceeding 100 Wh/L without precipitation or degradation issues that plague metal-based systems
Solution Approach 2:
The patent designs organic redox-active compounds with specific molecular characteristics (functional groups, aromatic cores, substituents) that enhance local solubility and intermolecular interactions. This local optimization of molecular structure enables high concentration stability while maintaining high energy density
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 use of these materials in redox flow batteries achieves energy densities greater than 100 Wh/L and reduces reliance on mined materials, addressing solubility and cost challenges while maintaining stability across a wide temperature range.
Implementation Method 1
During the discharge cycle of the redox flow battery, a first redox species may be oxidized in the negative half-cell which generates one or more electrons
Implementation Method 2
Ions are exchanged across the ion permeable membrane such that the two half-cells maintain charge neutrality
Implementation Method 3
melting the mixture to form the low-transition temperature material, wherein the low-transition temperature material has a melting point of less than 100° C.
Data Source
AI summary
A redox flow battery may include: a positive half-cell comprising a catholyte; a negative half-cell comprising an anolyte; and an ion permeable membrane, wherein the ion permeable membrane separates the catholyte and the anolyte, and wherein the catholyte, the anolyte, or both comprise a low-transition temperature material comprising: a redox-active phase; and an ionically conducting organic salt.