The project, published in Nature this week, uses a different way to control the high speed release of energy stored in isotopes of materials. This differs from nuclear batteries that use the release of radioactive ions and electrons from fissile material and have a long lifetime but a low energy transfer rate.
Dr. James Carroll at the US Army Research Laboratory's Power Components Branch and his team used a specific isotope of molybdenum where energy could be stored in an excited form of the atomic nucleus. This energy lasts for about seven hours, and can be released on a much shorter time scale by a new process involving the atomic shells around the nucleus. Creating a "hole" in an atomic shell, a free electron falling into that shell transferred just the right (small) amount of energy to the nuclei and, like a switch, caused a controlled release of the greater stored energy.
The effect was described 40 years ago but this is the first practical demonstration, working with researchers in Australia and Poland.
The concept used in the demonstration was published in 2012 by Carroll and a research collaborator from Russia's Joint Institute for Nuclear Research. Full-scale work to turn the concept into a real experimental design and to perform the necessary experiments began in mid-2014 with work in Australia and at the ATLAS lab at the Argonne National Laboratory in the US. Analysis of the more than 10 terabytes of data continued into early 2017 before the submission to Nature.
The aim is to develop smaller batteries with more energy to power the equipment soldiers use on the battlefield.
"Efforts are underway to develop new tools for the Army of the future, whether in enhancing the ability to understand the battlespace, better protecting the soldier, or moving more quickly and efficiently," said Carroll. "However, without sufficient energy and power, none of these improvements are feasible. Thus, there is clearly a strong motivation to expand