Semi-Solid Redox Flow Battery Electrolyte Energy Density
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional redox flow batteries have relatively low energy density due to limitations in the solubility of metal ion redox couples in liquid solvents, which restricts their power and energy storage capabilities.
Innovation Solution
The introduction of semi-solid or condensed ion-storing liquid reactants in redox flow energy storage devices, where at least one of the electrode active materials is a flowable ion-storing composition capable of taking up or releasing ions during operation, including compounds like ketones, diketones, and fluorinated derivatives, to enhance energy storage capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional liquid solvents are used in redox flow batteries, then the device can operate with good fluidity, but the energy density is limited due to solubility constraints of metal ion redox couples
Solution Approach 1:
The patent changes the physical state parameter of the electrolyte from conventional liquid to semi-solid slurry form. This parameter change enables higher concentration of redox-active materials (improving energy density) while maintaining pumpable flow characteristics (maintaining ease of operation). The slurry formulation with controlled particle size distribution and viscosity achieves both high energy density and efficient fluid transport.
Solution Approach 2:
The patent creates a composite electrolyte system combining solid redox-active particles suspended in liquid conductive medium. This composite approach allows the system to benefit from both the high capacity of solid materials and the fluidity of liquid electrolytes, resolving the contradiction between energy density and transport efficiency.
2Quantity of substance
If the concentration of redox-active materials is increased to improve energy density, then the specific energy increases, but the viscosity increases making fluid transport less efficient
Solution Approach 1:
The patent optimizes the particle size distribution parameter of the slurry to maintain low viscosity even at high redox-active material concentrations. By controlling particle size and distribution, the system achieves high specific energy without excessive viscosity increase that would impede fluid transport.
Solution Approach 2:
The patent applies different functional components locally within the slurry: conductive particles for electron transport, redox-active particles for energy storage, and liquid medium for ion transport. This local quality differentiation allows high concentration of redox materials while maintaining overall fluidity through the conductive liquid phase network.
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 of redox flow batteries, enabling higher power and energy density storage, suitable for applications like electric vehicles and stationary energy storage, while minimizing the accumulation of solids and maintaining low viscosity for efficient fluid transport.
Implementation Method 1
an ion-permeable medium separating the positive and negative current collectors
Implementation Method 2
at least one of the electrode active materials comprises a flowable ion-storing redox composition which is capable of taking up or releasing ions during operation of the device
Data Source
Figure 1A
Figure 1B~1C
Figure 1D
AI summary
Redox flow devices are described in which at least one of the positive electrode or negative electrode-active materials is a semi-solid or is a condensed ion-storing electroactive material, and in which at least one of the electrode-active materials is transported to and from an assembly at which the electrochemical reaction occurs, producing electrical energy. The electronic conductivity of the semi-solid is increased by the addition of conductive particles to suspensions and/or via the surface modification of the solid in semi-solids (e.g., by coating the solid with a more electron conductive coating material to increase the power of the device). High energy density and high power redox flow devices are disclosed. The redox flow devices described herein can also include one or more inventive design features. In addition, inventive chemistries for use in redox flow devices are also described.