Researchers create a new method to increase the energy generated from seaweed

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An international team with participation of the Material Science Institute of Madrid (ICMM-CSIC) has increased the electricity generated from alginate, a biodegradable polysaccharide derived from marine seaweeds, by combining it with MXenes, conductive materials made of titanium and carbon or nitrogen which have properties similar to graphene. The developed method, published in the journal  ACS Applied Materials & Interfaces, will allow for the charging of small devices and autonomous energy generation.

MXenes are highly conductive materials with atomic thickness, similar in this regard to graphene. They were discovered in 2011 by the scientist Yury Gogotsi, who is also a co-author of this work. Additionally, MXenes are hydrophilic, so they can be dispersed and processed in water, giving them certain advantages over graphene (which, as a carbon-based material, cannot be dispersed in water). The processing of this material is "more environmentally friendly" because it uses water and "does not require potentially toxic organic elements," explains Bernd Wicklein, a researcher at ICMM-CSIC and an author of the study.

"In our work, we combined two different types of MXenes with alginate, which is edible, biodegradable, and biocompatible," Wicklein details. Although this is not the first time electricity has been generated using this biopolymer, the project's goal was to enhance the triboelectric properties of alginate to develop renewable energy through nanogenerators: "We created synergistic effects that increased alginate's capacity to generate energy," says the ICMM scientist.

The researcher explains that the triboelectric effect occurs with movement: "You have two surfaces that, when moving, come into contact, and spontaneously, electrons jump from one to the other." When these surfaces are separated, the electron charge between them becomes unbalanced, "and this is precisely the electricity we collect," he adds.

The goal is to generate energy on a small scale: "The power we generate with this movement, which occurs with just the vibrations of the environment, is about 300 milliwatts per square meter. This cannot compete with a solar panel, but it doesn't need to, because it is used for other purposes, such as small devices and, above all, for autonomous energy generation."

This way, small devices like thermometers, light bulbs, or telemedicine devices such as autonomous sensors can be powered. In this context, the researcher mentions previous work in which similar triboelectric devices (but with chitin instead of alginate) were used to analyze patients' urine and detect prostate issues: "The device is activated by the movement generated by the falling urine, and with artificial intelligence algorithms, we analyze those patterns to relate them to pathologies."

Moreover, the formula created is perfectly scalable: "There are already companies producing MXenes on a kilogram scale and selling them, and alginate, our base polymer, has no limitations," Wicklein notes, emphasizing that the process is "easy, economical, and ecological, because everything is water-based." "With this, you can already create large sheets," concludes the scientist, who confesses that he hopes these investigations will move out of the lab and reach society: "We provide ideas that others can also implement."