When taking on today’s most exciting clean energy research, Energy Frontier Research Center (EFRC) scientists are bound to run into challenges requiring exotic instrumentation or uncommon techniques they do not have at their disposal. Luckily, for many such cases, the Department of Energy (DOE) has an answer: user facilities, the playgrounds of the scientific world, where researchers can access extraordinary resources to further their scientific goals. These user facilities and their state-of-the-art capabilities are invaluable for the EFRC mission.
The DOE is home to 28 user facilities spanning many disciplines. Of those, 12 are in Basic Energy Sciences, which is also home to the EFRCs. Use of the facilities is awarded competitively and is free of charge for non-proprietary work, including research to be published in peer-reviewed journals. Generally, scientists apply for use of an instrument such as a synchrotron beamline or powerful microscope. If their experiments are approved, the scientists travel to the facility — often just for a few hours or days, but sometimes for many months — to conduct their experiments before returning home. Some EFRCs include user facility scientists as members, enabling frequent, high-level collaboration.
User facilities cover a broad scope of capabilities and are used by EFRC researchers for everything from nanoscience expertise to neutron scattering and supercomputing resources. Here are a few examples of EFRC breakthroughs made possible by user facilities.
Observing gas adsorption with synchrotron X-rays
High-flux, broadband X-rays are a coveted resource, and accelerating electrons in a synchrotron light source is the best-known way to make them. The Center for Gas Separations Relevant to Clean Energy Technologies (CGS) uses the Advanced Light Source (ALS), a user facility at Lawrence Berkeley National Laboratory, to directly observe how gas molecules adsorb in the pores of metal-organic frameworks (MOFs). Efficient gas separations, including the capture of carbon dioxide released when burning fossil fuels, could drastically reduce the carbon footprint of many industrial processes. MOFs, porous crystals that act like molecular sponges, make excellent adsorbents for many small molecules such as carbon dioxide and hydrogen. This makes them promising materials for gas separations, but the ways gases interact with MOF pore walls at various pressures are not fully understood.
Leveraging the remarkable flux of the ALS, CGS researchers have developed gas cells that allow them to collect single-crystal X-ray diffraction data from the MOFs at controlled gas pressures. The researchers dose the MOFs with gases and watch as the adsorbed species fit into unique adsorption sites within each pore. Gases adsorb to the strongest binding sites, and as the pressure increases, additional sites are filled. This fundamental understanding of an adsorption mechanism, realized thanks to the capabilities of both the CGS and the ALS, will guide future development of MOF materials for energy-efficient gas separations.
Understanding radiation damage in alloys
Safe nuclear power requires materials that can withstand high radiation doses at elevated temperature, which in turn necessitates knowing how materials respond to these extreme environments. When studying a promising class of radiation-resistant materials called concentrated solid-solution alloys, the Energy Dissipation to Defect Evolution (EDDE) EFRC has utilized many user facilities’ advanced characterization capabilities. An EDDE team directly observed defect propagation under high radiation doses using the Intermediate Voltage Electron Microscopy (IVEM)-Tandem Facility at Argonne National Laboratory. This user facility allowed the team to bombard their samples with krypton ions inside an electron microscope, providing real-time insight into defect propagation and confirming hypotheses based on other experimental and molecular dynamics results.
Another team included neutron scattering from the Spallation Neutron Source in their characterization toolbox to understand how atoms in these metal mixes organize. Instead of finding total randomness, as expected, their results show short-range order throughout the materials due to preferential bonding between certain atoms. These findings will help the nuclear power community design better radiation-resistant materials.
Studying lithium-ion battery components
Improvements to lithium-ion battery chemistry promise to advance energy storage for devices from cell phones to electric cars. Researchers from the Nanostructures for Electrical Energy Storage (NEES) EFRC, including members of Sandia National Laboratories’ Center for Integrated Nanotechnologies user facility, one of five DOE nanoscale science research centers, have developed new methods to probe the electrochemistry of nanoscale electrode materials. Through this collaboration, the NEES team developed a technique to measure electron diffraction patterns of nanoscale electrode materials as they react.
The electrode material, here titanium dioxide, accepts lithium ions as the battery is charged. As this happens, the team measures changes in individual crystal domains’ structure using diffraction patterns collected with an electron microscope. With this new technique, they demonstrated that crystal domains smaller than around 25 nanometers react through a different mechanism than the bulk material, and their results suggest the smaller domains could lead to batteries with faster kinetics. Previous attempts to study this system were limited to measuring the average composition of many crystals. Because the new technique developed by NEES researchers isolates diffraction patterns from individual crystal domains, behaviors unique to nanoscale electrode materials were observed. The NEES team’s exciting results offer the community new tools to understand electrode materials and pave the way for the better design of nanostructured battery components.
Today and tomorrow at user facilities
User facilities provide EFRCs with the tools needed to make the rich scientific discoveries discussed here. Due to their ever-advancing capabilities, these facilities allow researchers to understand energy-relevant systems with precise temporal and spatial resolution. Moving forward, these resources will be critical in pushing the boundaries of clean energy science and developing the disruptive energy technologies our society needs.
