Apatite-type materials without interstitial oxygens show high oxide-ion conductivity by overbondingMay 16, 2018
Scientists at Tokyo Institute of Technology (Tokyo Tech) ; Nagoya Institute of Technology; National Institute of Technology, Niihama College; Neutron Science and Technology Center, The Comprehensive Research Organization for Science and Society (CROSS); and Japan Atomic Energy Agency have shown the overbonding of channel oxygens in La-rich apatite-type lanthanum silicates, rather than the presence of the interstitial oxygens, to be responsible for the high oxide-ion conductivity. This concept of "high oxide-ion conductivity by overbonding" opens the door for designing better ion conductors, which could be useful in energy conversion and environmental protection.
Solid oxide electrolytes have been extensively studied due to their wide range of applications in solid oxide fuel cells (SOFCs), oxygen membranes, catalysts, and gas sensors. Electrolytes with high oxide-ion conductivity at temperatures below 600 °C are required to decrease the operation temperature of SOFCs. Professor Susumu Nakayama at National Institute of Technology, Niihama College has discovered in 1995 the extremely high oxide-ion conductivity in the intermediate temperature range below 600°C, which has encouraged many researchers to study the structural origin of this phenomenon.
It was believed that the high oxide-ion conductivity of apatite-type materials is due to interstitial oxygens. However, in this novel study, Professor Masatomo Yashima, Dr. Kotaro Fujii at Tokyo Institute of Technology (Tokyo Tech), and their colleagues have shown that apatite-type materials contain Si vacancies, but not oxygen interstitials. The Si vacancies in the materials have originally been proposed by Professor Koichiro Fukuda at Nagoya Institute of Technology.
Through single-crystal neutron diffraction studies using the SENJU diffractometer installed at MLF, J-PARC facility (Figure 1), they were able to accurately determine the crystal structures of the apatite materials La9.333Si6O26 and La-rich La9.565(Si5.826□0.174)O26 (□ denotes Si vacancy) including occupancy factors, atomic displacement parameters, and spatial distributions of oxygen atoms. They also measured the density and oxide-ion conductivity of the two materials. In this work, La9.565(Si5.826□0.174)O26 was selected because of its high oxide-ion conductivity.
By structure analyses using the diffraction data, the researchers found Si vacancies, no interstitial oxygens, and larger positional disorder of the oxide ion at the O4 site in the apatite channel as compared to the basic material La9.333Si6O26 (Figure 2). The lower activation energy for the oxide-ion conduction along the c axis was found to be the main reason for the higher oxide-ion conductivity of La9.565(Si5.826□0.174)O26 as compared to La9.333Si6O26. The excess La yielded the overbonding of the O4 oxide ion in La9.565(Si5.826□0.174)O26 as compared with La9.333Si6O26, which led to higher oxide-ion mobility and conductivity of La9.565(Si5.826□0.174)O26 with Si vacancies (Figure 2). Density measurements by the Archimedes method supported the presence of Si vacancies in La9.565(Si5.826□0.174)O26.
Thus, the researchers proposed that excess La cations are responsible for overbonded channel oxygens along the c axis, which leads to highly anisotropic atomic displacement and high oxygen mobility. Hence this novel concept of "high oxide-ion conductivity by overbonding" may be useful for designing better ion conductors.
Tokyo Institute of Technology
Related Technology Articles:
More use of technology led to increases in attention, behavior and self-regulation problems over time for adolescents already at risk for mental health issues, a new study from Duke University finds.
The transfer of technology brings ideas closer to commercialization. The transformation happens in several steps, such as invention, innovation, building prototypes, production, market introduction, market expansion, after sales services.
Imagine patterning and visualizing silicon at the atomic level, something which, if done successfully, will revolutionize the quantum and classical computing industry.
Pioneering research by Professor Paul Lewis of Swansea University's Medical School into one of the most common lung diseases in the UK, Chronic Obstructive Pulmonary Disease, has led to the development of a new technology that can quickly and easily diagnose and monitor the condition.
Tecnalia leads EFFIPRO (Energy EFFIcient PROcess of Engineering Materials) project, which shows a new manufacturing process using powder metallurgy.
A team of researchers at Friedrich-Alexander-Universität have achieved an important milestone in the quest to develop efficient solar technology as an alternative to fossil fuels.
For this episode of BioScience Talks, we're joined by Gene Drive Committee co-chair James P.
The same technology used by the entertainment industry to animate characters such as Gollum in 'The Lord of The Rings' films, will be used to help train elite athletes, for medical diagnosis and even to help improve prosthetic limb development, in a new research center at the University of Bath launched today.
Carbon capture and storage could be used to mitigate greenhouse gas emissions and thus ameliorate their impact on climate change.
It has been thought technically difficult to achieve projection mapping onto a moving/rotating object so that images look as though they are fixed to the object.
Related Technology Reading:
Irresistible: The Rise of Addictive Technology and the Business of Keeping Us Hooked
by Adam Alter (Author)
“One of the most mesmerizing and important books I’ve read in quite some time. Alter brilliantly illuminates the new obsessions that are controlling our lives and offers the tools we need to rescue our businesses, our families, and our sanity.” —Adam Grant, New York Times bestselling author of Originals and Give and Take
Welcome to the age of behavioral addiction—an age in which half of the American population is addicted to at least one behavior. We obsess over our emails, Instagram likes, and Facebook feeds; we binge on TV episodes... View Details
Rise of the Robots: Technology and the Threat of a Jobless Future
by Martin Ford (Author)
The New York Times-bestselling guide to how automation is changing the economy, undermining work, and reshaping our lives
"Lucid, comprehensive, and unafraid...;an indispensable contribution to a long-running argument."--Los Angeles Times
Winner of the 2015 FT & McKinsey Business Book of the Year Award
Top Business Book of 2015 at Forbes
One of NBCNews.com 12 Notable Science and Technology Books of 2015
What are the jobs of the future? How many will there be? And who will have them? As technology continues to accelerate and machines begin taking care of... View Details
Soonish: Ten Emerging Technologies That'll Improve and/or Ruin Everything
by Kelly Weinersmith (Author), Zach Weinersmith (Author)
The instant New York Times bestseller!
A Wall Street Journal Best Science Book of the Year!
A Popular Science Best Science Book of the Year!
From a top scientist and the creator of the hugely popular web comic Saturday Morning Breakfast Cereal, a hilariously illustrated investigation into future technologies -- from how to fling a ship into deep space on the cheap to 3D organ printing
What will the world of tomorrow be like? How does progress happen? And why do we not have a lunar... View Details
The Technology Tail: A Digital Footprint Story (Communicate with Confidence)
by Julia Cook (Author), Anita DuFalla (Illustrator)
A cute, creative story about children and their texts, tweets, posts and pics. Don t be mean and irresponsible! That s the straight-to-the-point advice Screen has for young readers who are active on social media. Whether tapping out messages on their computers, tablets or phones, Screen wants kids to know their words will follow them for life, creating a digital trail that can't be erased. A timeless message to a new generation just learning how to navigate the fast-changing digital age. Written for children in grades 1-6, this storybook uses rhymes and colorful illustrations to grab their... View Details
Technology: A World History (New Oxford World History)
by Daniel R. Headrick (Author)
Today technology has created a world of dazzling progress, growing disparities of wealth and poverty, and looming threats to the environment. Technology: A World History offers an illuminating backdrop to our present moment--a brilliant history of invention around the globe. Historian Daniel R. Headrick ranges from the Stone Age and the beginnings of agriculture to the Industrial Revolution and the electronic revolution of the recent past. In tracing the growing power of humans over nature through increasingly powerful innovations, he compares the evolution of technology in different... View Details
Technology: A Reader for Writers
by Johannah Rodgers (Author)
Read. Write. Oxford.
Technology: A Reader for Writers focuses on the timely and vital subject of information and communications technologies and presents a range of contemporary and classic articles that invite students to consider and engage with questions related to how, why, and in what ways we may be able to critically reflect on ourselves and societies by writing and thinking about technology. Accompanied by group-discussion questions and writing prompts that ask students to engage with many of the same information and communications technologies they are... View Details
Engineering: An Illustrated History from Ancient Craft to Modern Technology (100 Ponderables)
by Tom Jackson (Editor) (Author), Tom Jackson (Editor)
From ancient aqueducts to soaring skyscrapers, explore engineering milestones over the centuries.
Combining engaging text with captivating images and helpful diagrams, renowned science writer Tom Jackson guides readers through the history of Engineering in the 7th installment of the groundbreaking PonderablesTM series.
Engineering is all around us. From our bridges, tunnels and skyscrapers, to our cars, computers and smartphones, engineering shapes our world and influences just about everything we see and do. And it s been that way for longer than you might think. From the... View Details
Information Technology Project Management
by Kathy Schwalbe (Author)
Gain a strong understanding of IT project management as you learn to apply today's most effective project management tools and techniques with the unique approach found in INFORMATION TECHNOLOGY PROJECT MANAGEMENT, 8E. This book emphasizes the latest developments and skills to help you prepare for the Project Management Professional (PMP) or Certified Associate in Project Management (CAPM) exams. While this edition reflect content from the latest the PMBOK Guide, it goes well beyond the Guide to provide a meaningful context for project management. Hundreds of timely examples highlight IT... View Details
Assistive Technologies: Principles and Practice, 4e
by Albert M. Cook PhD PE (Author), Janice Miller Polgar PhD OT (Author)
It’s here: the latest edition of the one text you need to master assistive strategies, make confident clinical decisions, and help improve the quality of life for people with disabilities. Based on the Human Activity Assistive Technology (HAAT) model, Assistive Technologies: Principles and Practice, 4th Edition provides detailed coverage of the broad range of devices, services, and practices that comprise assistive technology, and focuses on the relationship between the human user and the assisted activity within specific contexts. Updated and expanded, this new edition features... View Details
Milady Standard Nail Technology (MindTap Course List)
by Milady (Author)
Milady Standard Nail Technology, 7th Edition is packed with new and updated information on several important topics including infection control, manicuring, pedicuring, chemistry, UV gels, and the salon business. Brand new procedural photography enhances step-by-step instructions. Also included, is a new "Why Study?" section at the beginning of each chapter, outlining the importance of understanding the concepts presented. Chapter objectives have also been revised to provide measureable, outcomes-based goals that can later be assessed using the end-of-chapter review questions. This latest... View Details