Researchers at the Department of Energy's Oak Ridge National Laboratory, in collaboration with Sandia National Laboratories and Clemson University, have made a significant advance in the development of lightweight polymer membranes for clean energy applications. These membranes are fundamental components in fuel cells, devices that convert chemicals into electrical energy. The pursuit of durable and stable membranes is seen as a critical step towards achieving more efficient zero-emission power sources.
In their quest for this goal, the team employed neutron scattering and computational models to study the behavior of polymeric electrolyte membranes. According to a recent report by the Oak Ridge National Laboratory, they discovered how the addition of ethanol, a potential clean energy fuel, can be used to manipulate the structure of ionic clusters within the membranes. This manipulation effectively controls the membranes' conductivity and mechanical properties, a critical factor for designing lighter power sources – an attribute that, ironically, carries a lot of weight when optimizing the energy efficiency of vehicles powered by fuel cells.
"Within these membranes, ions form clusters that allow the transport of the protons," Lilin He, a neutron scattering scientist at ORNL, explained, as per the Oak Ridge National Laboratory. The team's growth in understanding the cluster changes in response to solvents is expected to underpin enhanced clean energy solutions. The discovery came after the insight that controlling the size and shape of these clusters is key in forming effective lightweight membrane electrolytes.
Aided by small-angle neutron scattering at the High Flux Isotope Reactor (HFIR) on the GP-SANS instrument, along with computational studies from Lawrence Berkeley National Laboratory's National Energy Research Scientific Computing Center (NERSC), researchers were able to pinpoint how ethanol alters these ionic clusters. "The alcohol molecules wrapped around the ions and opened the clusters just enough to allow the material to organize in a more stable way," Gary S. Grest, a computational physicist at Sandia National Laboratories, shared in a way that the very electrons themselves seemed to be organizing a toast to scientific progress, as cited by the Oak Ridge National Laboratory.
This work opens a pathway to create optimized materials for better clean energy platforms. The findings were funded by DOE's Office of Science and highlight the value that the user facilities like HFIR and NERSC offer to the global research community. UT-Battelle manages ORNL for the DOE's Office of Science, which stands at the forefront of supporting basic physical science research in the United States. Full details of the study can be accessed at the ORNL news portal.
