Category Physics

Particles are pulled out of a dispersion to form a ‘pearl necklace’, by applying an electric field through a needle-shaped electrode. Credit: Ming Han

Rozynek, a researcher at Adam Mickiewicz University in Pozna, Poland, demonstrated something that looked almost like magic. When he poked a needle-shaped electrode into a mixture of micron-sized, spherical metal particles dispersed in silicone oil, a sphere stuck to its end. As Rozynek pulled the electrode out of the dispersion, another sphere attached to the first sphere, and then another to the second sphere, and so on, until a long chain formed. “The spheres behaved like magnetic beads, except no magnetism was involved,” said Prof. Luijten, NW McCormick School of Engineering. “The particles have no tendency to cluster...

Illinois professor Paul Braun and Hailong Ning, the director of research and development at Xerion Advanced Battery Corporation, led a research team that developed a method for directly electroplating lithium-ion battery cathodes. Credit: Photo by L. Brian Stauffer

The process that makes gold-plated jewelry or chrome car accents is now making powerful lithium-ion batteries. Researchers at the University of Illinois, Xerion Advanced Battery Corporation and Nanjing University in China developed a method for electroplating lithium-ion battery cathodes, yielding high-quality, high-performance battery materials that could open the door to flexible and solid-state batteries.

Traditional lithium-ion battery cathodes use lithium-containing powders formed at high temperatures...

The authors observed in real-time the transformation of a HfO2 nanorod from its room temperature to tetragonal phase, at 1000° less than its bulk temperature. Nanorod surfaces and twin boundary defects (pictured here) serve to kinetically trap this phase.

Materials research creates potential for improved computer chips and transistors. The inorganic compound hafnium dioxide commonly used in optical coatings has several polymorphs, including a tetragonal form with highly attractive properties for computer chips and other optical elements. However, because this form is stable only at temperatures above 3100F – scientists have had to make do with its more limited monoclinic polymorph. Until now...

On the left is a low-resolution scanning transmission electron microscopy (STEM) image of a ferroelectric material that is continuously graded from barium strontium titanate (BSTO, top) to barium titanate (BTO, bottom). The material is grown on a gadolinium scandate (GSO) substrate buffered by a strontium ruthenate (SRO) bottom electrode. To the right are local nanobeam diffraction-based 2D maps of a-axis and c-axis lattice parameters that confirm large strain gradients in the ferroelectric material. The material is promising as electrically-tunable capacitors with extreme temperature stability. Credit: Anoop Damodaran/Berkeley Lab

Scientists have greatly expanded the range of functional temperatures for ferroelectrics, a key material used in a variety of everyday applications, by creating...