Halogen-Sequestering Battery Membrane for Crossover Control
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Solution Overview
Problem
Existing halogen-based batteries face challenges in confining halogens to the cathode side to prevent self-discharge and improve efficiency, as current solutions like microporous membranes and ion-exchange membranes are costly and inefficient in suppressing halogen crossover.
Innovation Solution
The use of a polymeric halogen sequestering agent (HSA) that complexes with halogens, reducing their diffusion across the semipermeable barrier between the anode and cathode, thereby enhancing halogen confinement and battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If microporous membranes or ion-exchange membranes are used to reduce halogen crossover, then halogen confinement is improved, but manufacturing cost increases significantly
Solution Approach 1:
The patent employs a polymer coating applied to standard microporous membranes that provides effective halogen confinement without requiring expensive ion-exchange membranes. The polymer layer acts as a cost-effective barrier that prevents halogen crossover while allowing the underlying membrane structure to perform its function, significantly reducing manufacturing costs while maintaining reliability.
Solution Approach 2:
The invention creates a composite structure by combining a standard microporous membrane with a polymer coating layer. This composite approach leverages the pore structure of the membrane for ion transport while the polymer layer provides halogen confinement, achieving both functions at lower cost than ion-exchange membranes alone.
2Reliability
If molecular complexing agents like MEPBr are used to complex halogens, then halogen reactivity is reduced, but polybromide accumulation forms an oily phase near the cathode
Solution Approach 1:
The patent removes the problematic molecular complexing agent from the electrolyte solution and replaces it with a polymer coating on the membrane. This extraction of the complexing function from the bulk solution to the membrane interface eliminates the formation of oily polybromide phases while maintaining halogen reactivity control through the polymer's complexing moieties embedded in the coating.
Solution Approach 2:
The polymer coating acts as an intermediary layer between the cathode and the bulk electrolyte. It provides complexing sites for halogens at the membrane interface, controlling halogen behavior without allowing extensive polybromide formation in the bulk solution that would create oily phases.
3Reliability
If existing membrane systems are used to prevent halogen crossover, then some confinement is achieved, but bromine crossover suppression remains insufficient
Solution Approach 1:
The patent modifies the properties of the microporous membrane by adding a polymer coating with specific complexing moieties. This changes the interaction parameters between the membrane and halogen species, enhancing the membrane's ability to retain bromine through chemical complexing while maintaining ion transport, thereby significantly reducing bromine crossover and energy loss.
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 halogen crossover by up to 70% over 5 hours, improving energy efficiency and reducing the cost of battery components compared to traditional methods.
Implementation Method 1
a polymeric halogen sequestering agent (HSA) that complexes with halogens, reducing their diffusion across the semipermeable barrier
Implementation Method 2
reducing their diffusion across the semipermeable barrier between the anode and cathode
Implementation Method 3
a semipermeable barrier, which permits the exchange of electrolyte ions but not of the halogen
Implementation Method 4
During the charging step, zinc is electroplated on the carbon anode, and Br2 is evolved at the carbon cathode
Implementation Method 5
storing charge through a change in oxidation state (e.g. vanadium redox) or through an electrodeposition such as the zinc-bromine battery
Implementation Method 6
Zinc is oxidized to zinc ions on the anodes
Implementation Method 7
the Br2 is released from the complex and subsequently reduced to Br− ions on the cathodes
Implementation Method 8
storing charge through a change in oxidation state (e.g. vanadium redox)
Data Source
AI summary
The present specification relates to a battery, comprising an anode, a cathode, an electrolyte disposed between the anode and the cathode, a halogen in contact with the cathode, and a metal in contact with the anode, wherein the halogen is in contact with a polymeric halogen sequestering agent (HSA) which is a polymer comprising a moiety capable of sequestering the halogen.