image: Future Formula E cars could be powered by batteries that feature up to 30 percent increased energy density. view more
Credit: ORNL
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BATTERIES - Off to the races ...
Drivers of Formula E cars may soon no longer have to change cars midway through the race, thanks to a battery coating technology developed by XALT Energy of Michigan and Oak Ridge National Laboratory. By depositing a nanoscale layer of alumina on oxide cathodes, researchers have increased battery energy density by up to 30 percent. "This work highlights the dominant effects of surface chemistry on active material performance," the authors wrote in their paper published in Scientific Reports. ORNL co-author David Wood III noted that the results are encouraging not only for drivers of race cars but also for passenger electric vehicle manufacturers and consumers. This new technology could be on the racetrack as early as October 2017. [Contact: Ron Walli, (865) 576-0226; wallira@ornl.gov]"
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Cutline: Future Formula E cars could be powered by batteries that feature up to 30 percent increased energy density.
MATERIALS - Energy-saving roofs ...
An anti-soiling highly reflective and water-resistant roof coating developed at Oak Ridge National Laboratory and evaluated at Lawrence Berkeley National Laboratory has produced encouraging results. The coating based on superhydrophobic particles resulted in only 3.3 and 4.9 percent reductions in solar reflectance and water contact angle, respectively, after aging tests equivalent to three years. Over the life of a roof, this could mean substantial savings in energy costs, reduced urban heat, smog abatement and lower peak power demand. "Highly water-resistant and solar-reflective coatings for low-slope roofs are potentially among the most economical retrofit approaches to thermal management of the building envelope," ORNL's Georgios Polyzos said. [Contact: Ron Walli, (865) 576-0226; wallira@ornl.gov]
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Cutline: A superhydrophobic additive increases resistance to water, soiling and microbial growth.
PHYSICS - Illuminating traps...
Energy-sapping defects in solar cell material can be revealed with an unprecedented, dual-imaging method established by researchers at Oak Ridge National Laboratory. ORNL scientists scanned hybrid perovskite films to measure "dark" electronic trap states in complex photovoltaic materials, providing a visual tool for insight into more durable, high-performing devices. Their approach allows reliable and direct mapping of the poorly understood phenomenon hindering solar cell technology advances. The result can be considered an "efficiency map" of the material with energy leaks pinpointed. "With our imaging method, other researchers can now see, understand and ultimately address these trap states for better energy conversion efficiency of solar cell technology," lead author and ORNL microscopist Mary Jane Simpson said. The paper is published in Journal of Physical Chemical Letters. [Contact: Ashanti B. Washington, (865) 241-0709; washingtonab@ornl.gov]
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Cutline: This map depicts locations of trap states (in purple) in a hybrid perovskite film, with emission and overall photoexcitation distributions measured directly using multimodal ORNL optical imaging techniques.
MATERIALS- Microwave microscopy of ferroelectric domains ...
Research led by Oak Ridge National Laboratory and published in Nature Communications explored building blocks of future electronics -- ferroelectric materials in which topological defects called domain walls can be created by an electric field and detected by an alternating current. The study led by Alexander Tselev, Sergei Kalinin and Petro Maksymovych of the Center for Nanophase Materials Sciences, a DOE Office of Science User Facility at ORNL, found that domain walls in two ferroelectric oxides were great electrical conductors at microwave frequencies, despite being insulators for direct current. In fact, their alternating current conductivity rivaled that of doped silicon. "These findings motivate the potential for alternating current conduction for oxide electronics and other materials with poor direct current conductivity, particularly at the nanoscale," noted Maksymovych. [Contact: Dawn Levy, (865) 576-6448; levyd@ornl.gov]
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Cutline: Microwave imaging (left) reveals conducting ferroelectric domain walls (right) in lead zirconate titanate. Before microwave microscopy, it was difficult to detect electrically conducting ferroelectric domains. Measurements also suggest the "rough" shape of these walls, indicated with dotted lines in the inset (far right), enables the alternating current conductivity.
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