By Nick Gilbert
A Low-cost, eco-friendly and rechargeable battery has been developed by a team of researchers headed by Sri Narayan, professor of chemistry at the USC Dornsife College of Letters, Arts and Sciences. This battery could be utilized to store energy in solar power facilities on rainy days. The research was funded by the Advanced Research Projects Agency for Energy (ARPA-E), a division of the U. S. Department of Energy.
The air-breathing battery utilizes the chemical energy produced by means of oxidation of iron plates which are exposed to the air. Currently, these batteries can store between 8 to 24 hours' worth of energy.
Narayan stated that this is the future, since air is free and iron is cheap. Description about the battery will appear in the Journal of the Electrochemical Society on July 20.
The federal government and California utilities have shown their interest in this project. A patent is pending for this battery. Though these iron-air batteries were developed many decades ago, they were inefficient because of hydrolysis, which is a chemical reaction of hydrogen generation that occurs within the battery and sucks 50% of the battery’s energy.
The iron-air batteries developed by Narayan and his team were 10x more efficient, reducing energy loss by 4%. The researchers were able to achieve this by adding a small quantity of bismuth sulfide which helps in reducing wasteful hydrogen generation. Bismuth is a part of the active ingredient present in Pepto-Bismol, giving the pink remedy its name.
Narayan stated that a small amount of bismuth sulfide will not compromise the potential of an eco-friendly battery. Though by adding mercury or lead the efficiency of the battery would have improved significantly, but it would not be safe.
Governor Jerry Brown in April 2011 approved The California Renewable Energy Resources Act, mandating that 33% of the state’s utilities must generate power by the end of 2020 from renewable energy sources.
Narayan stated that the traditional way of pumping water uphill into reservoirs and then releasing it downward to spin electricity-generating turbines was not feasible or practical since these resources suffer water loss due to evaporation. Hence an effective way of storing energy is needed.
At present, Narayan and his team are continuing with their research to make the battery more efficient using less material and to store more energy.