EPFL scientists develop hydrogel-based 3D printing that yields metals 20× stronger

Researchers at the École Polytechnique Fédérale de Lausanne(EPFL) have developed an innovative additive manufacturing method that begins with hydrogels rather than metal-infused resins. The team’s approach allows them to infuse a printed gel framework with metal salts, convert them into dense nanoparticles, and ultimately produce metals and ceramics that reportedly withstand 20 times more pressure than structures made by conventional 3D printing.

Their technique works as follows: first, a water-based gel scaffold is 3D printed. This “blank” gel structure is then soaked repeatedly in metal salt solutions, triggering a chemical conversion that deposits metal nanoparticles throughout the gel network. Through multiple cycles, typically 5 to 10 infusions ,the metal concentration increases until the scaffold is saturated. Finally, the gel is removed by heating, leaving behind a dense metallic or ceramic structure that mirrors the original shape. (Source)

This method addresses two major issues that hamper conventional metal additive manufacturing: porosity and excessive shrinkage. Past techniques often produce parts with internal voids and significant dimensional changes due to material contraction, weakening both geometry and mechanical performance. In contrast, the EPFL approach yields parts that are much denser and more stable.

Tests on gyroid lattice structures made from iron, copper, and silver showed dramatic improvements. The new components sustained 20 times the pressure of prior equivalents while exhibiting only about 20 % shrinkage, compared to 60–90 % shrinkage typical in older methods.

The flexibility of the process is another notable advantage. Because the hydrogel template is agnostic to material—being just a carrier structure—the same printed scaffold can produce parts in different metals, ceramics, or composite forms, depending on which salts are used in infusion.

EPFL researchers envision applications in fields requiring lightweight, high-strength, complex geometries, such as energy systems, sensors, biomedical devices, or porous catalysts. The control over geometry plus improved material strength may unlock new possibilities in these domains.

One caveat: the multi-cycle infusion process is relatively time-intensive compared to direct metal printing techniques. The research team is exploring automation and robotics to speed up processing and make the method more suitable for industrial scale.

This development represents a paradigm shift in additive manufacturing: instead of embedding material choices at the printing stage, material composition becomes a post-printing decision, a reversal of conventional flow in 3D printing.