Zinc-Bromine Battery Sequestration Liquid to Prevent Bromine Diffusion
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Solution Overview
Problem
Current bromide sequestration methods in batteries, such as ion exchange resins, membrane filtration, and complexing with amines or quaternary ammonium compounds, face issues like incomplete removal, high costs, fouling, reversibility, and potential contamination, necessitating a simple and effective method for bromine sequestration to enhance battery performance and lifespan.
Innovation Solution
A zinc-bromine battery design incorporating a cathode made of conductive carbon-based materials, an anode of conductive materials resistant to bromine, and a halogenated solvent as a sequestration agent that forms a less mobile complex with bromine, preventing its diffusion and enhancing energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ion exchange resin is used for bromide sequestration, then bromide ions are removed from electrolyte, but complete removal is not achieved and resin requires frequent regeneration
Solution Approach 1:
The patent extracts the bromine sequestration function from traditional ion exchange resins and implements it through a dual-electrode electrochemical system. The cathode specifically captures bromine species from the electrolyte through electrochemical reduction, separating the sequestration function from the traditional resin medium and enabling complete removal without regeneration needs.
Solution Approach 2:
The patent replaces the mechanical/chemical ion exchange mechanism with an electrochemical mechanism. Instead of relying on resin ion exchange sites that become saturated, the system uses electrochemical reduction at the cathode to convert bromine species to bromide, which can be continuously removed through the electrochemical reaction without material exhaustion.
2Reliability
If membrane filtration is used for bromide sequestration, then bromide ions are filtered from electrolyte, but membrane fouling occurs reducing effectiveness
Solution Approach 1:
The patent replaces the physical filtration mechanism with an electrochemical mechanism. Instead of using membranes that physically block and foul with bromide species, the system uses electrochemical reduction at the cathode to transform bromine species into soluble bromide ions that are then removed through the electrochemical reaction, eliminating fouling issues entirely.
3Reliability
If amines or quaternary ammonium compounds are used for bromine complexing, then bromide ions are sequestered, but the process is reversible causing recontamination
Solution Approach 1:
The patent replaces the reversible chemical complexation mechanism with an irreversible electrochemical reduction mechanism. Instead of forming reversible complexes that can dissociate, the system uses electrochemical reduction at the cathode to convert bromine species to bromide ions, a transformation that does not reverse under operating conditions, ensuring stable and permanent sequestration.
Solution Approach 2:
The patent changes the fundamental parameter of the sequestration mechanism from chemical equilibrium-based complexation to electrochemical potential-based reduction. By applying a reducing potential at the cathode, the system drives the bromine to bromide conversion irreversibly, changing the stability parameter from equilibrium-controlled to potential-controlled, ensuring no recontamination occurs.
4Reliability
If flow batteries are used for bromide removal, then bromine is pumped into storage tanks, but system complexity increases
Solution Approach 1:
The patent merges the bromide removal function with the normal battery discharge function. The cathode serves dual purposes: as the electroactive component for power generation and as the bromine sequestration site. This integration eliminates the need for separate flow battery tanks and pumping systems, reducing overall system complexity while maintaining effective bromide removal.
Solution Approach 2:
The patent makes the cathode universal by giving it multiple functions: electroactive power generation during discharge and bromine sequestration during charge/discharge cycles. This multi-functionality eliminates the need for dedicated bromine removal equipment, simplifying the overall system architecture while achieving reliable bromide ion removal.
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 battery achieves efficient bromine sequestration, preventing bromine escape and improving performance, while being cost-effective, safe, and easy to install, thus addressing the limitations of existing methods.
Implementation Method 1
a halogenated solvent as a sequestration agent that forms a less mobile complex with bromine, preventing its diffusion
Data Source
AI summary
This present patent application discloses is a battery with improved bromide sequestration wherein the battery includes parts such as an anode, which comprised of an electrically conductive material; a cathode that comprised of an electrically conductive carbon-based material; an electrolyte and a liquid used for bromine sequestration. The bromine sequestration liquid is nonpolar, immiscible, or virtually immiscible in water or aqueous-based gel and has a density greater than that of water. The bromine sequestration agent is selected from tetrabromoethane, tetrachloroethylene, carbon tetrachloride, tetrachloroethane, trichloroethane, tribromoethane, or a combination thereof. However, tetrabromoethane or tetrachloroethylene are preferred.