Application of sulfonated polyetheretherketone based ion exchange membrane in batteries
DATE：2024/8/8 15:14:40 / READ： / SOURCE：This station
This type of battery has the advantages of long lifespan, fast response, and low maintenance costs, and has a very broad application prospect in many industry fields. However, this type of battery also has its own shortcomings. The perfluorosulfonic acid cation membrane used in the battery has the disadvantages of high vanadium ion permeability and high price, which seriously restricts the commercial application of vanadium flow batteries. Therefore, the whole industry is looking for suitable ion exchange membranes to improve efficiency, extend lifespan, and reduce battery costs.
We are currently conducting research on the modification of sulfonated polyetheretherketone (SPEEK) membranes with high sulfonation degree, in order to find ways to improve the performance and stability of SPEEK based ion exchange membranes. During the research process, we found that the SPEEK membrane has high ion selectivity when the sulfonation degree is 67%. The vanadium flow battery assembled using this membrane has good battery performance. In addition, when studying the film-forming solvent, we found that the film-forming solvent N, N-dimethylformamide (DMF) has better performance. Below, the editor will present our research results in the form of a table:
|
Research medium |
research findings |
Battery characteristics |
|
Composite membrane with PVDF |
SPEEK has good compatibility with PVDF, and PVDF effectively inhibits the swelling of the composite membrane. The high chemical stability of PVDF helps to improve the stability of the composite membrane |
|
|
Composite film with P (VDF-HFP) |
The SPEEK/P (VDF-HFP) composite film exhibits a phase separation structure, but due to the weak interaction between SPEEK and P (VDF-HFP), this type of composite film has good chemical stability. |
|
|
Composite membrane with SBA-15 |
The - SO3H group in SPEEK interacts with the - OH group in SBA-15 through hydrogen bonding, effectively improving the thermal stability of the composite membrane. |
When the SBA-15 mass fraction is 20%, the battery assembled with this composite membrane operates at a current density of 60 mA cm-2. The Coulombic efficiency and energy efficiency of the battery are 96.3% and 88.1%, respectively, which are 4.1% and 7.1% higher than those of the Nafion 117 membrane battery. |
|
Blended film with PAN |
There is an acid-base interaction between the - SO3H acidic group in SPEEK and the - C ≡ N basic group in PAN. Further results show that as the mass fraction of PAN increases, the acid-base interaction of the blend film continues to strengthen, and the water absorption rate and vanadium ion permeability of SPEEK/PAN blend film continue to decrease, while the ion selectivity continues to improve. |
The all vanadium flow battery assembled with S/PAN-20 membrane showed a Coulombic efficiency and energy efficiency of 96.2% and 83.5%, respectively, when operating at a current density of 80 mA cm-2, which was 5.1% higher than that of the Nafion 117 membrane battery. |
Author：admin