Recycling of used batteries is always a big challenge. Regardless of how many improvements to current energy storage devices are made, sooner or later they all end up at the same place. We hope this is a battery recycling facility, but the reality is that often it is simply the landfill site.
Now, a team of researchers from University of Illinois, have taken up the task to handle this problem by developing a fully functioning battery, made of biocompatible materials, which dissolves in water after storing energy for three weeks.
The device is very small in size, one-square-centimeter, with a tiny magnesium-foil anode, which is 50 micrometers in thickness and an iron, molybdenum or tungsten cathode, with a thickness of only 8 micrometers. For the electrolyte, the scientists used a phosphate-buffered saline solution, and the whole package they wrapped in the biodegradable polyanhydride polymer. At this stage, the battery can sustain its voltage for a day, but the team is currently improving the technology and hoping to achieve a boost in power density.
The findings of the research appeared in the journal Nature earlier this week. Because the concentrations of the chemical elements in the materials are very small, besides helping the environment and eliminating the recycling problem, the batteries are also suitable to be used inside the human body. As one of the researchers on the project, John Rogers, points out, clinical trials have already demonstrated that the released concentrations of elements during the degradation process are unlikely to cause damages to human health.
Other applications of the technology include tracking of oil spills and other water polluting elements. All in all, if these batteries become commercial, they might well lead the way to the development of the ever-so-needed biodegradable electronic gadgets.
Image (c) University of Illinois