Flow Battery Electrolyte Composition for High Iron Salt Stability
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Solution Overview
Problem
Existing redox flow batteries face limitations in increasing iron salt concentration in their electrolytes without compromising battery stability or requiring larger tank sizes, as high concentrations lead to decreased columbic efficiency and compatibility issues with auxiliary components.
Innovation Solution
A high energy density electrolyte composition is developed, incorporating redox active iron species with concentrations up to 2.0 M, along with supporting salts like potassium, ammonium, calcium, and manganese salts, which maintains stability and compatibility with existing IFB components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If iron salt concentration in the electrolyte is increased to increase battery capacity, then the energy density improves, but the columbic efficiency decreases and battery stability deteriorates
Solution Approach 1:
The patent changes the chemical parameters of the electrolyte by introducing multiple supporting salts (potassium salt, ammonium salt, calcium salt, manganese salt) in specific concentration ranges. This allows the iron salt concentration to be increased to 2.0 M or higher while maintaining battery stability through the buffering and complexing effects of the supporting salts, thus resolving the contradiction between increasing iron salt concentration and maintaining battery stability
Solution Approach 2:
The patent creates a composite electrolyte system by combining iron salt (redox-active species) with multiple supporting salts (potassium salt, ammonium salt, calcium salt, manganese salt). This composite composition enables high iron salt concentration (≥2.0 M) while the supporting salts work synergistically to maintain columbic efficiency and prevent precipitation, resolving the contradiction between quantity increase and reliability maintenance
2Quantity of substance
If iron salt concentration is increased without adding supporting salts, then the energy density improves, but the electrolyte becomes incompatible with auxiliary components and columbic efficiency decreases
Solution Approach 1:
The patent modifies the electrolyte composition parameters by adding specific supporting salts (potassium salt 0.5-1.5 M, ammonium salt 0.5-2.5 M, calcium salt 0-1.5 M, manganese salt 0-0.25 M) that change the chemical environment. This allows high iron salt concentration (≥2.0 M) to be compatible with existing IFB auxiliary components like pumps and plumbing, resolving the adaptability issue
Solution Approach 2:
The supporting salts act as intermediaries between the high concentration iron salt and the auxiliary components. These salts buffer the electrolyte chemistry, prevent unwanted side reactions, and ensure compatibility with pumps, pipes, and other auxiliary components while enabling high iron salt concentration for increased energy density
3Quantity of substance
If electrodeposition electrolytes are used for high iron salt concentration, then the solubility limit is exceeded, but the electrolyte requires high temperatures and frequent replacement
Solution Approach 1:
The patent changes the temperature parameter from high (above 60°C required for electrodeposition electrolytes) to low (ambient or below 25°C). The supporting salt composition enables high iron salt solubility and stability at these lower temperatures, eliminating the need for high-temperature operation and associated infrastructure
Solution Approach 2:
The patent changes the operational durability parameter by introducing supporting salts that prevent precipitation and maintain stability over thousands of cycles. This eliminates the frequent electrolyte replacement required with electrodeposition electrolytes, enabling long-term operation without maintenance
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 composition allows for increased battery capacity without enlarging the electrolyte tanks, maintaining stability and efficiency over multiple cycles, and reducing the need for frequent electrolyte replacement.
Implementation Method 1
redox active species dissolved in the electrolyte and having a concentration of at least 2.0 M
Data Source
AI summary
Systems and methods are provided for an electrolyte for a flow battery comprising a redox active species and a plurality of supporting salts dissolved in the electrolyte. The redox active species having a concentration greater than 2.0 M and the plurality of dissolved supporting salts comprising a potassium salt, and ammonium salt, a calcium salt, and a manganese salt.