A European research team involving Hamburg University of Technology (TUHH) and Deutsches Elektronen-Synchrotron DESY has developed a novel way for converting mechanical energy into electricity – by using water confined in nanometre-sized pores of silicon as the active working fluid.
In a study published in Nano Energy (Elsevier), scientists from CIC energiGUNE (Spain), the University of Ferrara(Italy), the Hamburg University of Technology (TUHH) and DESY(Germany), the University of Silesia in Katowice (Poland), and Riga Technical University (Latvia) — supported by the Cluster of Excellence “BlueMat – Water-Driven Materials” — demonstrate that the cyclic intrusion and extrusion of water in water-repellent nanoporous silicon monoliths can produce measurable electrical power.
Electricity generated by friction in tiny pores
The developed system, known as an Intrusion–Extrusion Triboelectric Nanogenerator (IE-TENG), uses pressure to repeatedly force water into and out of nanoscale pores. During this process, charge generation occurs at the interface between the solid and the liquid. This is a type of friction electricity that often occurs in everyday life. An example that everyone is familiar with: walking across a PVC carpet with shoes on. Electrons transfer from one body to another, accumulating a charge that is suddenly discharged when a third body is touched. For example, when touching a door handle, the charge flows away and you get a small electric shock.
The achieved energy conversion efficiency of up to 9% ranks among the highest ever reported for solid–liquid nanogenerators. “Even pure water, when confined at the nanoscale, can enable energy conversion,” says Prof. Patrick Huber, spokesperson of the BlueMat – Water-Driven Materials Excellence Cluster at the Hamburg University of Technology (TUHH) and DESY. Dr. Luis Bartolomé (CIC energiGUNE) adds: “Combining nanoporous silicon with water enables an efficient, reproducible power source — without exotic materials, but just by using the most abundant semiconductor on earth, silicon, and the most abundant liquid, water.”
Materials design as the key
“A crucial step was the development of precisely engineered silicon structures that are simultaneously conductive, nanoporous, and hydrophobic,” explains Dr. Manuel Brinker from the Hamburg University of Technology. “This architecture allows us to control the motion of water inside the pores — making the energy conversion process both stable and scalable.”The technology paves the way for autonomous, maintenance-free sensor systems — for example in water detection, sports and health monitoring in smart garments, or haptic robotics, where touch or motion directly generates an electrical signal. “Water-driven materials mark the beginning of a new generation of self-sustaining technologies,” emphasize the corresponding authors Prof. Simone Meloni (University of Ferrara) and Dr. Yaroslav Grosu (CIC energiGUNE).
Reference:
L. Bartolomé et al., Triboelectrification during non-wetting liquids intrusion–extrusion in hydrophobic nanoporous silicon monoliths,
Nano Energy 146 (2025) 111488.
DOI: 10.1016/j.nanoen.2025.111488
