Scanning the surface of lithium titanate
by Staff Writers
Sendai, Japan (SPX) Jul 07, 2017
Researchers at Tokyo Institute of Technology, Tohoku University and the University of Tokyo have applied advanced scanning methods to visualize the previously unexplored surface of a superconductor: lithium titanate (LiTi2O4).
LiTi2O4 is the only known example of a so-called spinel1 oxide superconductor. Its rarity makes LiTi2O4 of enormous interest to those studying the origins of superconductivity, as it has the highest superconducting transition temperature (of up to 13. 7 K) within this group of materials.
Although LiTi2O4 in bulk form has been studied for decades, little is known about its surfaces, owing to the difficulty of preparing suitable LiTi2O4 surfaces for further analysis.
Now, using a combination of experimental and theoretical methods, a team of researchers including Taro Hitosugi of Tokyo Tech and the Advanced Institute for Materials Research at Tohoku University, has obtained visual evidence of superconductivity on ultrathin LiTi2O4 films, marking a milestone in surface science.
Published in Nature Communications, the study began with the detection of an unexpected energy "gap," hinting at the existence of superconductivity at the surface. Furthermore, their investigations revealed that the surface superconductivity is in different states from that of the bulk interior. The researchers used two experimental methods to visualise this finding: pulsed laser deposition2 (PLD), a technique that has enabled the production of high-quality LiTi2O4 films under vacuum conditions; and low-temperature scanning tunnelling microscopy/spectroscopy (STM/STS), for precise imaging of the surfaces.
"Imaging the atoms for the first time was surprising, as it's usually very difficult to observe the spinel-oxide atoms," says Hitosugi. "We then wanted to know the exact atomic arrangement on the surface, and in order to do that, we compared theory and experiment."
So, to delve deeper into how the atoms are arranged, the team made theoretical calculations that led them to consider four types of surface cut from bulk LiTi2O4. By comparing these four types, the researchers found one - called the TiLi2-terminated surface - that matched their experimental observations.
Hitosugi explains that "knowing the accurate arrangement of atoms is the most important thing," as this knowledge will help to advance understanding of superconductivity at its thinnest limit, two-dimensional superconductivity at the surface.
In addition to the superconducting properties, knowing the atomic arrangements could lead to unveiling the mechanisms behind lithium-ion battery operations. The understanding of electrode surfaces is an essential step for designing next-generation lithium-ion batteries with higher capacity, enhanced life cycles and fast charging capabilities, because lithium ions migrate across the electrode surfaces.
As the study provides new directions for interface research, Hitosugi plans to collaborate with Tokyo Tech colleagues now working on solid-state electrolytes, specifically to improve understanding of the electrode-electrolyte interface (EEI), one of the hottest topics in battery research.
"Many people are interested in solid-state batteries - the future of lithium-ion batteries," he says. "Now that we know the surface atomic arrangement of this material, we can begin to simulate the operation of solid-state lithium batteries."
Melbourne, Australia (SPX) Jul 07, 2017
In the harshest of environments in far-east Russia, Monash scientists have played a leading role in the discovery of a new mineral, which could revolutionise the future of the mining industry. The mineral - Nataliyamalikite - is new, and did not exist before, explains Professor Joel Brugger, the lead author in a recently published paper in American Mineralogist. It contains thallium, ... read more
Space Technology News - Applications and Research
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.