#ionic conductivity

Innovative technique reveals that leaping atoms remember where they have been

University of Oxford researchers have used a new technique to measure the movement of charged particles (ions) on the fastest ever timescale, revealing new insights into fundamental transport processes. These include the first demonstration that the flow of atoms or ions possesses a "memory." The study, "The persistence of memory in ionic conduction probed by nonlinear optics," has been published in Nature. Whether charging a battery or pouring water, the flow of matter is one of the most fundamental processes in the universe. But a surprising amount remains unknown about how this occurs at the atomic scale. Understanding this better could help us solve a wide range of problems, including developing the materials needed for the technologies of tomorrow. In the new study, a team of researchers based at Oxford's Department of Materials and the Stanford Linear Accelerator (SLAC) National Laboratory in California made the surprising discovery that the movement of individual ions can be influenced by its recent past; in other words, there is "a memory effect." This means that, on the microscopic scale, history can matter: what a particle did a moment ago can affect what it does next.

First-ever wireless device developed to make magnetism appear in non-magnetic materials

Researchers at the UAB and ICMAB have succeeded in bringing wireless technology to the fundamental level of magnetic devices. The emergence and control of magnetic properties in cobalt nitride layers (initially non-magnetic) by voltage, without connecting the sample to electrical wiring, represents a paradigm shift that can facilitate the creation of magnetic nanorobots for biomedicine and computing systems where basic information management processes do not require wiring. The study was recently published in the latest issue of Nature Communications. Electronic devices rely on manipulating the electrical and magnetic properties of components, whether for computing or storing information, among other processes. Controlling magnetism using voltage instead of electric currents has become a very important control method to improve energy efficiency in many devices, since currents heat up circuits. In recent years, much research has been carried out to implement protocols for applying voltages to carry out this control, but always through electrical connections directly on the materials.

A super material applicable to batteries and other energy conversion devices

Scientists normally conduct their research by carefully selecting a research problem, devising an appropriate plan to solve it and executing that plan. But unplanned discoveries can happen along the way.

Mercouri Kanatzidis, professor at Northwestern University with a joint appointment in the U.S. Department of Energy's (DOE) Argonne National Laboratory, was searching for a new superconductor with unconventional behavior when he made an unexpected discovery. It was a material that is only four atoms thick and allows for studying the motion of charged particles in only two dimensions. Such studies could spur the invention of new materials for a variety of energy conversion devices.

"Our analysis results revealed that, before this transition, the silver ions were fixed in the confined space within the two dimensions of our material, but after this transition, they wiggled around," says Mercouri Kanatzidis, joint appointment with Argonne and Northwestern University

Kanatzidis's target material was a combination of silver, potassium and selenium (α-KAg3Se2) in a four-layered structure like a wedding cake. These 2D materials have length and width, but almost no thickness at only four atoms high.

Lithium ions flow through solid material

Scientists at the U.S. Department of Energy's (DOE) Argonne National Laboratory, in collaboration with researchers from Purdue University and Rutgers University, have merged materials science and condensed matter physics in a study of a promising solid material that conducts lithium ions.

The transport of ions, or charged atoms, through materials plays a crucial role in many electrical systems—from batteries to brains. Currently, the leading ion-conducting materials are liquid and organic, but the development of solid and inorganic ion conductors could have broad applications in energy conversion, bio-engineering and information processing.

In this study, samarium nickelate, a material that is also a solid, was shown to quickly transport lithium ions under certain conditions. The study was published in Proceedings of the National Academy of Sciences.

Simulations identify importance of lattice distortions in ion-conducting fuel cell materials

Ionic conduction involves the movement of ions from one location to another inside a material. The ions travel through point defects, which are irregularities in the otherwise consistent arrangement of atoms known as the crystal lattice. This sometimes sluggish process can limit the performance and efficiency of fuel cells, batteries, and other energy storage technologies.

Before determining which underlying properties of solid materials are crucial for improving these applications, researchers must better understand the factors that control ionic conduction. To pursue this knowledge, a multidisciplinary team from the US Department of Energy's (DOE's) Oak Ridge National Laboratory (ORNL) developed a computational framework to process and analyze large datasets of ion-conducting solids.

Using a dataset containing over 80 different compositions of materials called perovskites, the researchers focused primarily on identifying and optimizing those with promising proton conduction capabilities. These novel materials could enable the production of more reliable and efficient proton-conducting solid oxide fuel cells—energy storage devices that convert chemicals into electricity for practical uses such as powering vehicles.

The Scientific Research Notes Of S. Sunkavally (years: 2002-2011).