3D-printed TPMS electrodes boost redox batteries

3D-printed TPMS electrodes improve redox flow battery performance

An international research group led by the University of Waterloo has demonstrated that the internal geometry of electrodes, mathematically designed and fabricated with 3D printing, can substantially change the behavior of redox flow batteries. The Diamond geometry achieved the best results in balancing mass transport and hydraulic resistance.

TPMS structures instead of conventional porous materials

The group led by Professor Maxime van der Heijden redesigned the physical architecture of the electrode instead of modifying the battery chemistry.

The researchers used TPMS (Triply Periodic Minimal Surfaces) structures, periodically repeated minimal surfaces that offer precise geometric control. These architectures were fabricated via Digital Light Processing, a resin 3D printing technology.

After printing, the electrodes were subjected to heat treatment to convert them into conductive carbonaceous material. This process transforms the polymer resin into a carbonaceous structure suitable for electron transport.

Comparison between four geometries

The study simultaneously analyzed mass transport, pressure loss, available surface area, and electrochemical behavior.

The Diamond geometry proved particularly effective. It promoted the transport of redox species while keeping hydraulic resistance relatively low, a fundamental trade-off for practical applications.

Vanadium battery test

The proof of concept demonstrated the practical feasibility of the approach on a real laboratory vanadium redox flow battery.

The researchers installed one of the printed electrodes in a vanadium redox flow battery. The system achieved a voltage efficiency of 76% at a current density of 50 mA/cm².

This is a proof of concept, not a battery ready for installation on the electrical grid. However, it demonstrates an important principle for additive manufacturing in the energy sector.

Electrodes as fluid-dynamic components

The approach changes the design paradigm: the electrode becomes an engineered component instead of a material with a random structure.

In redox flow batteries, the electrode can be treated as a designed fluid-dynamic component. This contrasts with the traditional approach that accepts porous materials with a substantially random structure, such as conventional carbon felt.

3D printing makes it possible to simultaneously optimize multiple parameters: electroactive surface area, permeability, tortuosity of flow paths, and current distribution. The geometric control offered by TPMS makes this level of optimization possible.

Implications for stationary storage

Redox flow batteries separate power and energy more than conventional batteries, making them suitable for grid applications.

The work, published in the Journal of Energy Storage, opens up prospects for stationary energy storage. Redox flow batteries operate differently from lithium-ion cells: energy is stored in external liquid electrolytes, not primarily in solid electrodes.

This separation between power components (electrochemical stack) and capacity (electrolyte tanks) makes them scalable for grid applications. Optimizing the electrodes through additive manufacturing could reduce costs and improve the performance of these systems.

article written with the help of artificial intelligence systems