CO2-Formate Flow Battery Chemistry for Low-Overpotential Storage
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Solution Overview
Problem
Current redox flow batteries face high costs and inefficiencies due to the expense of redox flow chemistry active materials and system design, limiting their widespread commercialization and deployment for long-duration energy storage, particularly in converting carbon dioxide to formate for reversible energy storage.
Innovation Solution
The development of a redox flow battery system utilizing carbon dioxide, bicarbonate, or carbonate as the negative active material, with a reversible electrocatalyst like Pt(depe)2 for interconversion with formate/formic acid at low overpotentials, enhancing energy density and solubility, and using ferrocyanide/ferricyanide, Prussian white/Prussian blue, or bromide/bromine as positive active materials for efficient charge and discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional redox flow battery systems use traditional active materials, then the system can achieve basic energy storage function, but the cost is high and commercialization is limited
Solution Approach 1:
The patent replaces expensive traditional redox flow battery active materials with cheaper alternatives: using CO2/bicarbonate/carbonate as negative active material instead of conventional expensive electrolytes, and using abundant materials like ferrocyanide/ferricyanide, Prussian white/Prussian blue, or bromide/bromine as positive active materials. This substitution directly addresses the high cost barrier while maintaining functional reliability for long-duration energy storage
Solution Approach 2:
The patent changes the chemical parameters of the redox active materials from traditional expensive compounds to CO2-based carbonate/bicarbonate systems and abundant metal complexes. This parameter change in material composition enables cost reduction while the multi-electron processes in CO2/HCO2- conversion enhance energy density, improving commercialization prospects
2Quantity of substance
If the battery system uses CO2 to formate conversion, then energy density increases through multi-electron processes, but the Faradaic efficiency and selectivity must be maintained high
Solution Approach 1:
The patent employs an electrocatalyst as an intermediary to facilitate the CO2 to formate conversion. The electrocatalyst mediates the multi-electron transfer process, enabling high energy density through complete CO2 reduction while maintaining high Faradaic efficiency by providing a selective reaction pathway that minimizes competing side reactions and ensures precise electron-to-product conversion
3Loss of energy
If reversible electrocatalysis is achieved with minimal overpotential, then energy efficiency improves, but finding such catalysts is challenging
Solution Approach 1:
The patent changes the chemical parameters of the electrocatalyst to achieve minimal overpotential for CO2/HCO2- interconversion. By selecting specific electrocatalytic materials and optimizing their properties, the system achieves reversible electrocatalysis with minimal energy loss, directly addressing the overpotential challenge while the systematic approach to catalyst selection manages the complexity
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 approach significantly reduces costs by using cheaper materials, increases energy density through multi-electron processes, and achieves high Faradaic efficiency and selectivity in CO2/HCO2− conversion, enabling stable and efficient long-duration energy storage with minimal overpotential.
Implementation Method 1
The electrocatalyst converts carbon dioxide, bicarbonate, or carbonate into formate to store electron equivalents
Implementation Method 2
The electrocatalyst oxidizes formate to release the stored electrons and discharge
Implementation Method 3
Redox flow batteries offer an opportunity for economical, long duration (e.g., greater than 4 hour discharge time) energy storage
Data Source
AI summary
Redox flow battery systems utilizing the reversible interconversion between carbon dioxide, (or bicarbonate or carbonate) and formate/formic acid. The battery system comprises an electrocatalyst that converts carbon dioxide, bicarbonate, or carbonate into formate to store electron equivalents, and oxidizes formate to release stored electrons and discharge. A non-limiting example of an electrocatalyst that can be used for reversible interconversion of carbon dioxide and formate is Pt(depe)2.