Flow Electrochemical Cell With Neutralyte Layer for CO2 Capture
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Solution Overview
Problem
Current technologies face challenges in simultaneously achieving efficient carbon dioxide capture and electrical energy storage, particularly in integrating these functions into a single electrochemical cell with high areal power densities and cost-effectiveness, while also addressing the intermittent nature of renewable energy sources and the need for grid-scale energy storage.
Innovation Solution
The development of a scalable redox-flow battery (RFB) with a unique membrane-electrode assembly (MEA) that maintains a pH differential between electrodes, using a three-layer assembly of an intermediate neutralyte layer sandwiched between two ion-exchange membranes, allowing for efficient carbon dioxide capture from air or flue gas and energy storage through a synergistic combination of electrochemical processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional separate systems are used for carbon capture and energy storage, then each function can be optimized independently, but the system complexity and cost increase significantly
Solution Approach 1:
The patent combines carbon dioxide capture and electrical energy storage into a single integrated electrochemical cell. The cell simultaneously performs CO2 capture at the cathode through bicarbonate formation and energy storage through redox reactions, eliminating the need for separate capture and storage systems. This merging reduces overall system complexity while maintaining both functions.
Solution Approach 2:
The electrochemical cell is designed to perform multiple functions within a single device: it captures CO2 from flue gas or air, stores electrical energy through reversible redox reactions, and produces pure CO2 as a product. The same cell structure and electrolyte system support both carbon capture and energy storage operations, demonstrating multi-functionality that reduces system complexity.
2Power
If high areal power densities are achieved through pH differential, then energy storage efficiency improves, but membrane structure complexity increases
Solution Approach 1:
The membrane structure is segmented into three distinct layers: a cation-exchange membrane (CEM), a neutralyte layer, and an anion-exchange membrane (AEM). Each layer performs a specific function - the CEM allows cation transport, the neutralyte provides a neutral pH environment for CO2 release, and the AEM allows anion transport. This segmentation enables high areal power density through pH differential while keeping each individual layer relatively simple in structure.
Solution Approach 2:
Different regions of the membrane assembly have different pH characteristics and ion transport properties tailored to specific functions. The CEM region maintains high pH for CO2 capture, the neutralyte region provides neutral pH for CO2 release, and the AEM region facilitates anion transport. This local differentiation of properties enables high power density without requiring complex overall membrane structure.
3Object-generated harmful factors
If renewable energy sources are used to power the cell, then carbon neutrality is achieved, but the intermittent nature of renewable sources reduces energy storage reliability
Solution Approach 1:
The electrochemical cell enables continuous operation by using the stored electrical energy to drive CO2 capture during periods when renewable generation is insufficient. The redox reactions allow the cell to store energy during high renewable generation periods and release it during low generation periods, ensuring continuous CO2 capture operation and improving reliability despite the intermittent nature of renewable sources.
Solution Approach 2:
The cell operates by changing pH parameters through electrochemical reactions. During charging, the pH differential is established to enable CO2 capture; during discharging, the pH changes facilitate energy release. This dynamic parameter adjustment allows the system to adapt to variable renewable energy input while maintaining reliable operation and achieving carbon neutrality.
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 enables high areal power densities and cost-effective energy storage while achieving efficient carbon dioxide capture, enhancing the operational efficiency and profitability of power generation plants and manufacturing processes by integrating carbon capture and energy storage in a single electrochemical cell.
Implementation Method 1
a three-layer assembly consisting of an intermediate neutralye layer (NL) sandwiched between two ion-exchange membranes (IEMs) for selective transport of cations and/or anions
Implementation Method 2
The CC-RFB accomplishes the twin objectives of efficient carbon-dioxide capture and electrical energy storage in a single electrochemical cell
Implementation Method 3
electrochemical carbon capture (eCC)... capture of carbon-dioxide either directly from air or from a point source such as a flue gas
Data Source
AI summary
Described are flow electrochemical cells and systems using flow electrochemical cells that carry simultaneous CO2 capture and electrical energy storage. The flow electrochemical cells comprise a negative electrode configured to be in fluid communication with alkaline negative electrolyte, a positive electrode configured to be in fluid communication with acidic positive electrolyte, a first ion-exchange membrane in contact with the negative electrode, a second ion-exchange membrane in contact with the positive electrode, and an inert intermediate neutralyte layer between the first ion-exchange membrane and the second ion-exchange membrane.