Printing Power: Scientists Grow Ultra-Strong Materials with Innovative 3D Technique

EPFL researchers have pioneered a 3D printing method that grows metals and ceramics inside a water-based gel, resulting in exceptionally dense, yet intricate constructions for next-generation energy, biomedical, and sensing technologies.

3D printing has long promised to transform manufacturing, but turning precise prints into high-strength metals and ceramics has remained a major challenge. Traditional methods often produce materials that are porous, weak, and prone to warping, limiting their practical use — until now.

Researchers at EPFL’s School of Engineering, led by Dr. Daryl Yee, have developed a novel “growth-based” 3D printing method that overcomes these limitations. Their approach creates dense, ultra-strong metal and ceramic structures from a simple 3D-printed hydrogel scaffold, marking a breakthrough in additive manufacturing.

The Limits of Traditional 3D Printing

Vat photopolymerization, one of the most common 3D printing techniques, involves pouring a light-sensitive resin into a vat and selectively hardening it with a laser or UV light. While highly precise, this method is largely limited to light-sensitive polymers, restricting its application for engineering-grade metals or ceramics.

Previous attempts to convert these polymer prints into metals or ceramics often resulted in porous, warped, and structurally weak parts, making them unsuitable for demanding applications.

Growing Materials Layer by Layer

The EPFL team approached the problem differently. Instead of embedding metal precursors in a resin from the start, they 3D print a blank scaffold using a water-based hydrogel. This scaffold serves as a template, capturing the object’s full geometry.

The hydrogel is then infused with metal salts, which are chemically converted into metal nanoparticles throughout the structure. Repeating this “growth cycle” multiple times increases the metal concentration, gradually transforming the soft scaffold into a dense composite.

A final heating step burns away the hydrogel, leaving a solid metal or ceramic object that mirrors the original scaffold in shape but is far stronger and denser than materials produced with earlier methods. Because the material is introduced after printing, the same scaffold can be converted into different metals, ceramics, or composites, adding exceptional versatility.

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Strength Meets Complexity

To test their method, the team printed intricate gyroid lattices — mathematical structures that maximize strength while minimizing weight — using iron, silver, and copper.

Mechanical testing revealed that these materials could withstand up to 20 times more pressure than comparable polymer-to-metal parts, with shrinkage reduced to 20% compared to the typical 60–90% in traditional processes.

This combination of strength, precision, and complex geometry makes the technique ideal for advanced 3D architectures, including sensors, biomedical devices, and energy systems where lightweight yet durable materials are crucial.

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Applications and Future Outlook

The method could revolutionize energy conversion and storage, enabling high-surface-area metals for catalysis, heat management, and advanced electronics.

The EPFL team is now focusing on industrial scalability, including robotic automation of the repeated infusion steps to reduce production time, and exploring ways to further increase material density.

This growth-based approach represents a paradigm shift in additive manufacturing, allowing designers to choose the final material after printing rather than before — opening new possibilities for stronger, more versatile, and more sustainable 3D-printed structures.