To this day the majority of the world’s electricity comes from burning fossil fuels but fortunately, new and ingenious alternatives keep appearing. The latest one researchers have introduced uses protein nanowires to extract electricity from air moisture, its called Air-gen (air generator).
This new device is a thin film, just 10 microns thick made of nanoscale protein wired collected from the microbe Geobacter sulfurrenducens that can generate continuous electrical energy in the environment, according to the study published in the journal Nature.
The new device is the brainchild of microbiologist Derek Lovley and electrical engineer Jun Yao, both from the University of Massachusetts, Amherst.
"We are literally producing electricity from nothing. The Air-gen generates clean energy 24 hours a day, 7 days a week. It's the most amazing and exciting application of protein nanowires yet," explains Jun Yao, an electrical engineer at the University of Massachusetts Amherst and co-author of the paper.
It may sound like an exaggeration to "produce electricity from nothing," but the research describes how the air-powered generator can create electricity with nothing but the presence of air around it. The key is in the film of electrically conductive protein nanowires placed between two electrodes and also exposed to air. Pores in the film absorb atmospheric water vapour and a moisture gradient induces ionization, with positive charges diffusing in one direction and electrons in the other.
It is non-polluting and can be produced at a low cost. Unlike other renewable energy sources, Air-gen does not require sunlight or wind - it also works indoors - and can generate power even in areas with extremely low humidity, such as the Sahara desert.
Some attempts to produce electricity from new sources are based on incredibly expensive raw materials. However, the nanowire film, because it is formed by the bacterium Geobacter, is an affordable component. The electrodes were made of gold leaf, but replacing it with inert carbon also worked.
On a laboratory scale, Air-gen's energy density is high compared to most current renewable energy devices. The prototype produced 0.5 sustained volts/ cm2 at best, about one-fifth of a solar panel in full sunlight, with a current density of 17 µA/cm2.
The next step is to include the development of a small Air-gen "patch" that can power electronic devices such as health and fitness monitors and smartwatches, which would eliminate the requirement for traditional batteries. It could even be applied to mobile phones to eliminate periodic charging.
"The ultimate goal is to make systems on a large scale," he concluded. Yao.
Reference: Xiaomeng Liu, Hongyan Gao, Joy E. Ward, Xiaorong Liu, Bing Yin, Tianda Fu, Jianhan Chen, Derek R. Lovley, Jun Yao Power generation from ambient humidity using protein nanowires Nature, 2020; DOI: 10.1038/s41586-020-2010-9