Alkaline Ferrocyanide Flow Battery With Solid Catholyte Charge Storage
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Solution Overview
Problem
Ferrocyanide-based alkaline redox-flow batteries have limited energy density due to low solubility of ferrocyanide in alkaline media, leading to restricted charge storage capacity and increased costs, with existing solutions either reducing battery life or increasing material costs.
Innovation Solution
A redox-flow battery design incorporating a solid electroactive material in a catholyte reservoir container, using ferrocyanide/ferricyanide pair for charge transfer, which enhances energy density and reduces material costs by confining the solid material within a catholyte reservoir for increased charge storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ferrocyanide-based alkaline electrolyte is used to maintain high ionic conductivity, then electrical conductivity is improved, but energy density deteriorates due to low solubility of ferrocyanide in alkaline media
Solution Approach 1:
The patent introduces a solid electroactive material phase in addition to the liquid electrolyte phase, creating a two-phase system. This dimensional addition allows the system to overcome the solubility limitation of ferrocyanide in alkaline media by providing an additional reservoir for charge storage in the solid phase, thereby increasing energy density without compromising ionic conductivity in the liquid phase
Solution Approach 2:
The patent creates a composite system combining liquid electrolyte (catholyte) and solid electroactive material. This composite approach allows the system to simultaneously maintain the high ionic conductivity provided by the liquid alkaline electrolyte and achieve higher energy density through the added solid phase that can store additional charge beyond the solubility limit of dissolved ferrocyanide
2Quantity of substance
If concentration of active species is increased to improve energy density, then charge storage capacity is improved, but solubility limit of ferrocyanide in alkaline media is exceeded
Solution Approach 1:
By adding the solid phase dimension to the system, the patent enables charge storage beyond the solubility limit of ferrocyanide in alkaline media. The solid electroactive material acts as an additional charge reservoir that does not suffer from solubility constraints, allowing the system to achieve higher charge storage capacity while maintaining stable composition in the liquid electrolyte phase
3Quantity of substance
If pH of electrolyte is reduced to increase ferrocyanide solubility, then energy density is improved, but battery life deteriorates due to enhanced corrosion
Solution Approach 1:
Instead of changing the pH parameter of the electrolyte to increase solubility, the patent changes the physical state parameter by introducing a solid electroactive material phase. This allows the system to achieve higher effective concentration of active species without altering the alkaline pH conditions, thereby maintaining low corrosion rates and extending battery life while still improving 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 design significantly increases energy density and reduces material costs by allowing higher charge storage per volume, improving the overall efficiency and cost-effectiveness of the battery system.
Implementation Method 1
The ferrocyanide is a partially soluble species that is able to reversibly store energy through an electrochemical redox reaction
Implementation Method 2
storing charge in the solid electroactive material by charge transfer between the oxidized catholyte and the solid electroactive material
Data Source
AI summary
The present invention refers to a redox-flow battery (1) comprising a positive compartment (10) comprising a positive electrode (11) and a catholyte, wherein said catholyte is an alkaline ferrocyanide solution; a catholyte reservoir container (12) connected in fluid communication with the positive compartment (10) through at least one conduct (13) and said container (12) comprising catholyte and a solid electroactive material (14), wherein said solid electroactive material is confined within the container and is selected from the group consisting of a metal oxide, a metal hydroxide, a metal oxyhydroxide or a combination thereof; a negative compartment (20) comprising a negative electrode (21) and an anolyte, wherein said anolyte is an alkaline solution; an anolyte reservoir container (22) connected in fluid communication with the negative compartment (20) through at least one conduct (23) and said container (22) comprising anolyte; and a power/load source (40). In addition, the present invention is directed to an energy storage system comprising at least one redox-flow battery (1) as defined above, to a method of storing electricity comprising providing a redox-flow battery (1) as defined above, a method of delivering electricity comprising providing a redox-flow battery (1) as defined above, to the use of the redox-flow battery (1) as defined above to store or deliver electricity and to the use of the redox-flow battery (1) as defined above in renewable energy and electromobility sectors.