- Number 411 |
- April 14, 2014
Scientists at DOE's Brookhaven Lab have made the first 3-D observations of how the structure of a lithium-ion battery anode evolves at the nanoscale in a real battery cell as it discharges and recharges. The details of this research could point to new ways to engineer battery materials to increase the capacity and lifetime of rechargeable batteries.
“This work offers a direct way to look inside the electrochemical reaction of batteries at the nanoscale to better understand the mechanism of structural degradation that occurs during a battery's charge/discharge cycles,” said Brookhaven physicist Jun Wang, who led the research.
Two years after the Microscopy and Characterization Suite (MaCS) opened in the Center for Advanced Energy Studies at DOE's Idaho National Laboratory, the facility is booked solid. In fact, it has doubled the number of research hours logged in the last year.
The suite is open to external researchers and supports advanced microscopy for both radiological and nonradiological materials. National and international scientists from academia and private industry can access research tools here that will help answer some of today's most critical questions, especially with regard to nuclear materials science.
When geologist John Rakovan needed better tools to investigate whether a dazzling 217.78-gram piece of gold was in fact the world’s largest single-crystal specimen—a distinguishing factor that would not only drastically increase its market value but also provide a unique research opportunity—he traveled to the Lujan Neutron Scattering Center at DOE's Los Alamos National Laboratory to peer deep inside the mineral using neutron diffractometry. Neutrons, different from other probes such as X-rays and electrons, are able to penetrate many centimeters deep into most materials.
“The structure or atomic arrangement of gold crystals of this size has never been studied before, and we have a unique opportunity to do so,” the Miami University professor said.
Long thought to be unresponsive, oxygen adatoms, negatively charged oxygen ions stuck to a catalyst's surface, actually respond to ultraviolet light, according to scientists at DOE’s Pacific Northwest National Laboratory. The team made this discovery by coating the surface of common titanium dioxide with krypton reporters. When light strikes the metal oxide catalyst, the oxygen adatoms become electronically excited by reactions with electrons and/or holes created in the material by ultraviolet light. This excitation causes the adatoms to move and collide with -- and transfer energy to – the nearby krypton atoms, causing the atoms to depart.
"The adatoms could be an additional source of photochemical interactions on titanium dioxide or other transition metal surfaces," said Dr. Nikolay Petrik, a physical chemist at PNNL and one of two authors on the yearlong study. "Potentially, the adatoms could participate in other photochemical reactions."
Since early in the mission of the Fermi Gamma-ray Space Telescope, a number of scientists have noticed a fairly bright spot of gamma-ray light coming from the center of our galaxy, the Milky Way.
Using publicly available data from the telescope, a team of scientists at DOE’s Fermilab, the Harvard-Smithsonian Center for Astrophysics, the Massachusetts Institute of Technology and the University of Chicago now confirmed that the spectrum and spatial shape of the gamma-ray signal seems to match that predicted to come from annihilating dark-matter particles. The team developed maps showing that the galactic center produces more high-energy gamma rays than can be explained by known sources and that this excess emission is consistent with some forms of dark matter.