Multilayer Ion Exchange Membrane for Vanadium Redox Flow Battery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Vanadium redox flow batteries face challenges in preventing crossover of vanadium ions between the positive and negative electrode electrolyte liquids, which contaminates the electrodes and decreases battery performance, while also requiring high hydrogen ion permeability to enhance internal resistance and efficiency.
Innovation Solution
A multilayer ion exchange membrane with specific equivalent weight ranges for each ion exchange resin layer, including a first layer with ionomers of 500-750 g/mol, second and third layers with ionomers of 750-900 g/mol, and outer layers with ionomers of 900-1100 g/mol, effectively preventing vanadium ion crossover while maintaining high hydrogen ion conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-layer ion exchange membrane is used, then the structure is simple and manufacturing is easy, but it cannot effectively prevent vanadium ion crossover while maintaining high hydrogen ion permeability
Solution Approach 1:
The ion exchange membrane is divided into multiple layers (first layer with 500-750 g/mol ionomers, second layer with 750-900 g/mol ionomers, third layer with 900-1100 g/mol ionomers) where each layer has different equivalent weights to create a gradient structure that prevents vanadium ion crossover while maintaining hydrogen ion permeability
Solution Approach 2:
The membrane uses composite ionomer materials with different equivalent weights in each layer, combining the benefits of low EW materials (high proton conductivity) in the first layer with high EW materials (low vanadium ion permeability) in the outer layers to achieve both high hydrogen ion permeability and effective vanadium ion crossover prevention
2Use of energy by moving object
If ionomers with lower equivalent weight are used, then hydrogen ion permeability is high, but vanadium ion crossover increases
Solution Approach 1:
Different regions of the membrane have different ionomer equivalent weights tailored to local requirements: the first layer (in contact with electrolyte) uses low EW (500-750 g/mol) for high hydrogen ion permeability, while the second and third layers use progressively higher EW (750-900 g/mol and 900-1100 g/mol) to prevent vanadium ion crossover
Solution Approach 2:
The solution transitions from a single-layer to a multi-layer structure, adding the dimension of layering to create a gradient of equivalent weights that simultaneously satisfies both hydrogen ion permeability and vanadium ion crossover prevention requirements
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 multilayer ion exchange membrane effectively reduces vanadium ion crossover and enhances battery performance by maintaining high hydrogen ion permeability, leading to improved residual capacity, current efficiency, voltage efficiency, and energy efficiency during charge and discharge cycles.
Implementation Method 1
an ion exchange membrane is required
Implementation Method 2
the ion exchange membrane needs to have excellent acid resistance and oxidation resistance, and low permeability
Implementation Method 3
high hydrogen ion permeability
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present specification relates to an ion exchange membrane including a first ion exchange resin layer; and a second ion exchange resin layer and a third ion exchange resin layer each provided on both surfaces of the first ion exchange resin layer, wherein the second ion exchange resin layer and the third ion exchange resin layer each include an ionomer having a higher equivalent weight (EW) than an ionomer of the first ion exchange resin layer.