Flowable Semi-Solid Redox Composition for High Energy Density Batteries
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Solution Overview
Problem
Conventional redox flow batteries have a relatively low energy density due to the limited solubility of metal ion redox couples in liquid solvents, which restricts their power and energy storage capabilities, and increasing solubility can lead to corrosion and other operational issues.
Innovation Solution
The use of semi-solid or condensed liquid ion-storing redox compositions that include a mixture of liquid and solid phases, allowing for increased ion storage capacity and improved energy density, with specific embodiments featuring flowable semi-solid or condensed liquid ion-storing redox compositions that can be transported and reused within the battery, enhancing both power and energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the solubility of metal ion redox couples in liquid solvents is increased to improve energy density, then the energy storage capacity increases, but corrosion and operational issues worsen
Solution Approach 1:
The patent changes the physical state parameter of the redox composition from fully liquid to semi-solid or condensed liquid, allowing increased ion concentration without the harmful effects of high solubility in liquid solvents. This parameter change enables higher energy density while avoiding corrosion
Solution Approach 2:
The patent uses composite redox compositions containing both liquid and solid phases, combining the benefits of liquid flowability with the high ion storage capacity of solid phases. This composite approach achieves high energy density without the corrosion problems associated with increasing liquid solvent solubility
2Ease of manufacture
If conventional liquid solvent redox couples are used, then the battery can be constructed with simple components, but the energy density remains relatively low
Solution Approach 1:
The patent employs composite redox compositions with both liquid and solid phases, achieving high energy density while maintaining manufacturability. The semi-solid nature allows the composition to be pumped and handled like liquids while containing high concentrations of ion-storing solid particles
Solution Approach 2:
The patent changes the physical state of the redox composition to semi-solid or condensed liquid, fundamentally altering the concentration capability and energy density while maintaining flow properties necessary for practical battery operation
3Device complexity
If static electrode media are used in rechargeable batteries, then the device structure is simplified, but the power density and current extraction rate are limited
Solution Approach 1:
The patent introduces dynamic flow of semi-solid redox compositions through the battery, replacing static electrode media. This allows continuous replenishment of reactants at the electrodes, significantly increasing power density and current extraction rates while maintaining a relatively simple overall structure
Solution Approach 2:
The patent uses hydraulic flow of semi-solid compositions to transport ion-storing materials to and from the electrodes. This fluid dynamic approach enables high power density by continuously supplying reactants, overcoming the limitations of static electrode media
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 increases the specific energy and power density of redox flow batteries, enabling higher energy storage capacities while maintaining flowability and reducing operational challenges associated with increased solubility, such as corrosion.
Implementation Method 1
an ion-permeable membrane separating the positive and negative current collectors
Implementation Method 2
liquid state redox reactions are carried out at the positive and negative electrodes
Implementation Method 3
transporting the flowable semi-solid or condensed liquid ion-storing redox composition into the electroactive zone during operation
Implementation Method 4
the rate at which current can be extracted is also limited by the distance over which cations can be conducted
Data Source
AI summary
Redox flow devices are described including a positive electrode current collector, a negative electrode current collector, and an ion-permeable membrane separating said positive and negative current collectors, positioned and arranged to define a positive electroactive zone and a negative electroactive zone; wherein at least one of said positive and negative electroactive zone comprises a flowable semi-solid composition comprising ion storage compound particles capable of taking up or releasing said ions during operation of the cell, and wherein the ion storage compound particles have a polydisperse size distribution in which the finest particles present in at least 5 vol % of the total volume, is at least a factor of 5 smaller than the largest particles present in at least 5 vol % of the total volume.