As the global demand for renewable energy escalates, the intermittent nature of sources like wind and solar poses a challenge: storing excess energy for times of low production. Redox flow batteries (RFB) show promise for large-capacity stationary storage, but hurdles such as mass transport limitations and slow kinetics hinder their efficiency. In this context, the ERC-funded RECHARGE project will marry pulsatile flow with precisely structured 3D electrodes, aiming to elevate redox flow battery performance to new heights. With in-depth understanding and advanced engineering, the project aims for a power density of 1000 mW/cm² and a roundtrip efficiency exceeding 85 %.
The rise of additive manufacturing has opened the door to 3D electrode geometries with a regularly ordered pore network. Using structured 3D electrodes the mass transfer rate can be increased with several orders of magnitude compared to 2D and disordered 3D electrodes. Nonetheless, the mass transfer rate and hence the RFB power performance remains strongly dependent on the electrode geometry, flow field design and pumping power. By imposing dynamic flow regimes the mass transfer rate towards the electrode surface is enhanced. Although a significant increase in battery performance is to be expected when implementing dynamic flows with commercial 3D electrodes, their disordered geometry will still result in an inhomogeneous distribution of the active species and local concentration depleted zones. By combining dynamic flows with structured 3D electrodes, RECHARGE offers an innovative solution to ensure homogeneity throughout the electrode. When properly engineered, the electrode skeleton in combination with dynamic flows allow to precisely control mass transfer and flow distribution inside the RFB. Ultimately, RFBs will be developed within RECHARGE that surpass the state-of-the-art in terms of their cell polarisations, maximum power densities and energy capacity. To this end, the following objectives are set forth:
Objective 1: Development of 3D electrode materials that address the efficiency losses in the RFB.
Objective 2: Gain insight in dynamic flow profiles and electrode geometry on active species distribution.
Objective 3: Combine dynamic flows with structured 3D electrodes to diminish polarisation losses.
Objective 4: Integration of structured 3D electrodes in a dynamic redox flow battery.
