Did you know that the cocoon membranes of a silk moth contain trace amounts of several elements such as sodium, chlorine, potassium, magnesium, sulphur, calcium and copper, as well as carbon, nitrogen and oxygen? Well, that’s not even the most amazing part of this story. Scientists in India have discovered a way to harvest these elements and make electricity from them using water. A new study published in Scientific Reports suggests that silk moth cocoons can be used to generate clean electricity to power electronics and possibly provide a source of power in the iron ore industry and nuclear power plants.
Wetting the cocoon makes the trace elements in a silk moth cocoon form mobile charge-carrying ions, producing an electric current across the cocoon membrane. The researchers used this current to light an LED. They attached an aluminum electrode to the inner surface of a cocoon and a copper electrode to the outer surface, and exposed the cocoon to water vapor. Three such cocoons were connected in series to light an LED. The researchers also charged a moist silk cocoon with a direct current source to see if it was capable of acting as a capacitor — a device that stores charge. The study shows that it could power an LED for two to three minutes after the direct current was removed.
But James S. Brooks and Eden Steven, researchers at Florida State University who have been working on spider silk’s electrical properties, have reservations about the work and say that any absorbent material can do the same thing. “The observed effects are very likely due to the wet electrochemistry between the aluminum and copper [electrodes] and the ions present in the cocoon…In fact, any absorbent will work the same as long as some ions are present.”
But Sushil Kumar Singh, co-author of the paper and researcher at the Defense Research Development Organization, India is pressing on with the research and is planning to look into the use of silk moth cocoon as a battery and to commercialize it. He hopes the batteries could also be produced from the silk protein sericin, which is wasted during commercial textile production, though the current research was carried out on entire cocoons.
Via Sci Dev Net