Research progress of high-performance battery membrane materials

Recently, the research team of Li Xianfeng from the Energy Storage Technology Research Department of the Dalian Institute of Chemical Physics, Chinese Academy of Sciences has made new progress in the large-scale preparation and application of membrane materials for high-performance and low-cost alkaline system flow batteries.
The roll-to-roll membrane production process realizes the large-area preparation of non-fluorine cation-conducting membranes and its application in alkaline system flow battery energy storage technology
.

Based on the structural design of the ion-conducting membrane in the alkaline system and the previous research on the ion transport mechanism, the research team prepared kilogram-scale sulfonated polyetheretherketone polymer resin through electrophilic substitution reaction, and then used continuous roll-to-roll The non-fluorine cation exchange membrane material was prepared in large quantities in batches, and its application in the alkaline system flow battery was realized
.

The research team used the developed membrane material to integrate a 4-kilowatt alkaline zinc-iron flow battery stack.
Under the condition of a working current density of 80 mA/cm 2 , the energy efficiency of the stack can reach more than 85%

Experts said that this research is expected to improve the performance of the new generation of flow batteries, accelerate its transition from laboratory to large-scale application, and have a positive impact on reducing the cost of the new generation of flow battery energy storage technology and promoting the practical process of flow battery energy storage technology.
promotion

Energy storage is the key and supporting technology for building a new power system with new energy as the main body.
Flow battery energy storage technology has the advantages of safety, reliability, long life and high efficiency, and is the preferred technology for large-scale energy storage
.
Among them, reducing the cost, especially reducing the cost of the ion-conducting membrane material, the key material of the flow battery, is one of the keys to promote the practical process of the flow battery

At present, the research on ion-conducting membranes for alkaline system flow batteries is very limited.
Due to its excellent stability, perfluorosulfonic acid ion exchange membrane (Nafion) has become the preferred membrane material for current flow batteries and even alkaline system flow batteries.

.
However, Nafion membrane has problems such as complex production process, by-products in the production process that are harmful to the environment and human health, expensive, and low ionic conductivity in an alkaline system, resulting in low battery efficiency

　　However, in an alkaline system, the quaternary amine groups on the traditional non-fluorine anion-exchange membrane, the quaternary amine-type anion-conducting membrane, undergo Hoffman elimination and nucleophilic substitution reaction, which makes this type of membrane less stable

　　The study found that the membrane material prepared by the team has excellent alkali resistance stability due to its rigid skeleton structure and its charge characteristics.