Future storage systems for the energy transition: Polymer-based redox-flow batteries

Introduction

The efficient storage of electric energy represents a major challenge for a successful energy transition, enabling the utilization of fluctuating renewable resources also as base load. Redox-flow batteries (RFBs) are the only type of battery where intrinsically power and capacity can be varied independently from each other, making this type of battery perfectly suited for scalable stationary applications.

Alternative Solutions

RFBs based on aqueous electrolytes with organic/polymer active materials have the potential to be suitable alternatives for commercial metal-based RFBs, with a low CO2 footprint perfectly fitting the goals of the EU Green Deal.

Advantages of Polymer-Based RFBs

In particular, polymer-based RFB systems enable the use of cost-efficient dialysis membranes together with pH neutral table salt solutions as electrolytes.

Current Limitations

Nevertheless, systems still reveal restrictions in terms of capacity, lifetime, and temperature stability.

Project Goals

FutureBAT targets a breakthrough in the development of novel organic active materials for RFBs, by combining the search for new active entities with the improvement of current polymeric materials on the molecular level, thereby providing new functions/properties.

Key Research Questions

The key question will be how far polymeric electrolytes can be tuned by adjusting the molecular structure.

Innovative Approaches

Advanced polymer structures (including (hyper-) branched structures) and colloidal systems (with varied morphologies) as well as novel hybrid organic systems will provide access to hitherto unknown properties, e.g., new photo-rechargeable RFBs or RFBs having all charged species within one single tank.

New Technologies

Furthermore, new sensor systems (SOC and SOH) will be applied, which will also form the basis for novel 3D-printed lab cells for (high-throughput) screening.

Expected Outcomes

As the outcome, pioneering breakthroughs in the field of polymer-based RFBs will be enabled, surely targeting high risk/high gain step-changing research but built upon the know-how of one of the leading international research teams in this rather new field.