Researchers from Eindhoven University of Technology and the University of Waterloo have used a $350 3D printer to manufacture battery electrodes with precisely engineered internal geometries.
One shape in particular, a diamond lattice, achieved more than twice the mass-transfer performance of a simple grid while also producing much lower hydraulic resistance.
The preprint targets redox flow batteries, a grid-scale energy storage technology where liquid electrolytes are pumped through porous carbon electrodes to charge and discharge. These batteries are promising for storing wind and solar energy because their power and storage capacity can be scaled independently.
But the carbon fiber mats used as electrodes in today’s commercial systems, while offering plenty of surface area, resist flow like a dense sponge. The pressure losses associated with pushing liquid through them contribute to pumping requirements, and the researchers argue that electrodes shaped using mathematical surface equations can ease that resistance dramatically.
Evaluating Geometry Across Printed Electrodes
To test the idea, the researchers 3D printed four different electrode shapes and baked them at 1,000°C to convert the polymer into electrically conductive carbon. The process boosted carbon content from 71.5% to 94.2% by atomic composition. All four designs used the same porosity (70% open space) and repeating unit size (1 mm), providing a controlled basis for comparing their different architectures.
Of the four, the diamond geometry performed best. Flow simulations showed it distributed liquid most evenly through its channels, with a coefficient of variation of 1.01 versus 1.43 for the cubic geometry, suggesting fewer dead zones and fewer bottleneck channels. It also offered the largest surface area among the printed designs, 1.47 times that of the cubic grid, and the lowest electrical resistance.
Against a commercial carbon felt electrode, the contrast was sharper still. Across the four printed designs, pressure drops ranged from 14 to 80 kPa per meter at 10 cm per second. The felt hit 745 kPa per meter.
Beyond shape, the team also explored how porosity affects performance by testing gyroid electrodes at 90%, 70%, and 50% open space. The most open version outperformed the densest one at every flow speed tested, even though it had 2.8 times less surface area. At moderate flow conditions, the 90% gyroid delivered 134 milliamps per square centimeter versus 101 for the 70% cubic electrode.
For electrolytes where the chemical reaction itself is fast, having wide-open flow channels appears to matter more than cramming in extra surface. The researchers caution that this balance likely tips the other way for slower chemistries like vanadium, where more surface area helps compensate for sluggish reactions.
That surface area gap, in fact, remains the biggest weakness of printed electrodes overall. Gas adsorption measurements showed the commercial felt packed roughly 10 times more surface area per unit volume than the best printed design, and the advantage showed up clearly at high flow speeds, where the felt delivered higher current.
The 3D printed structures also shrank during baking and developed hollow internal walls as gases escaped, making it difficult to know the exact final geometry with certainty.
Still, a proof-of-concept test in a full vanadium redox flow battery achieved 76% voltage efficiency at 50 milliamps per square centimeter. Coulombic efficiency was lower at 71%, which the researchers attribute to vanadium-ion crossover and side reactions, potentially exacerbated by membrane damage from the rigid printed electrode pressing against it during assembly.
The fundamental tradeoff the study maps out will be familiar to anyone working on flow battery electrodes. Conventional materials tend to bundle high surface area with high flow resistance. TPMS geometries appear to offer a partial way around that coupling, sacrificing some surface area for substantially lower hydraulic losses.
Whether that exchange pays off likely depends on the specific chemistry inside the cell, and the researchers suggest that pairing these printing techniques with computational optimization could eventually produce electrodes tailored to particular battery chemistries and operating conditions.
Titled, “Enhancing Mass Transport in Redox Flow Batteries with 3D-Printed Triply Periodic Minimal Surface Electrode Structures,” the study was conducted by Maxime van der Heijden, Mojtaba Barzegari, Joey Aarts, Baichen Liu, and Antoni Forner-Cuenca.
Lowering Barriers to Battery Prototyping
At UCLA, researchers reported using resin 3D printing followed by high-temperature carbonization, to fabricate porous carbon electrodes for zinc-ion hybrid batteries. By expanding the internal surface area of the carbon scaffold and coating it with vanadium oxide, they achieved a sevenfold capacity gain over comparable devices.
The manufacturing pathway overlaps considerably with the one used in the Eindhoven study, suggesting that low-cost resin 3D printing followed by thermal conversion may have applications in architected carbon electrodes across multiple battery chemistries.
Elsewhere, Caltech researchers used DLP 3D printing to create complex polymer structures that were pyrolyzed at 1,000°C into carbon electrodes for lithium-ion batteries. The approach allowed them to increase electrode mass loading while reducing the transport-length penalty associated with thicker conventional electrodes, demonstrating how control over electrode geometry can be used to address performance tradeoffs.
3D Printing Industry is inviting speakers for its 2026 Additive Manufacturing Applications (AMA) series, covering Energy, Healthcare, Automotive and Mobility, Aerospace, Space and Defense, and Software. Each online event focuses on real production deployments, qualification, and supply chain integration. Practitioners interested in contributing can complete the call for speakers form here.
To stay up to date with the latest 3D printing news, don’t forget to subscribe to the 3D Printing Industry newsletter or follow us on LinkedIn.
Explore the full Future of 3D Printing and Executive Survey series from 3D Printing Industry, featuring perspectives from CEOs, engineers, and industry leaders on the industrialization of additive manufacturing, 3D printing industry trends 2026, qualification, supply chains, and additive manufacturing industry analysis.
Featured image shows the redox flow battery setup consists of a reactor connected to two beakers that serve as electrolyte tanks, with tubing running through a pump to circulate the liquid electrolytes through the battery. The redox flow battery is connected to a potentiostat, which collects and records the energy generated by the battery. Photo via University of Waterloo.
