Development of metastable phase advanced material synthesis technology

Development of metastable phase advanced material synthesis technology

The percentage of metastable phase palladium hydrides (HCP) generated was dependent on the palladium concentration in the aqueous palladium solution and the electron beam intensity and hydrogen content in the metastable phase. The percentage of metastable phase palladium hydrides (HCP) generated was dependent on the palladium concentration in the aqueous palladium solution and the electron beam intensity and hydrogen content in the metastable phase. Credit: Korea Institute of Science and Technology

Like the widespread interest in graphite and diamond, there is also a growing interest in metastable phases, which have different physical properties than those of stable phases. However, methods of manufacturing materials in metastable phase are very limited. New findings are published in the latest issue of Nature on the development of a new metastable phase synthesis method, which can drastically improve the physical properties of various materials.

A research team led by Dr. Chun, Dong Won of the Clean Energy Research Division, Korea Institute of Science and Technology (KIST; President: Yoon, Seok Jin), announced that they have successfully developed a new advanced metastable-phase palladium hydride (PdHx) material. In addition, they identified the growth mechanism.

A material with a metastable phase has more thermodynamic energy than that in the stable phase, but requires significant energy to reach the stable phase, unlike most other materials, which exist in the stable phase with low thermodynamic energy. The research team directly synthesized a metal hydride by culturing a material that can store hydrogen under a suitable hydrogen atmosphere, without dispersing hydrogen in a metal. In particular, they successfully developed a metal hydride in metastable phase with a novel crystal structure. Furthermore, they confirmed that the developed material in metastable phase had good thermal stability and twice the hydrogen storage capacity of a material with stable phase.

Development of metastable phase advanced material synthesis technology

Real-time analysis of the growth process of metastable palladium hydride nanoparticles in a liquid phase by transmission electron microscopy. Credit: Korea Institute of Science and Technology

To clarify the theoretical basis and scientific evidence for these findings, the research team used atomic electron tomography, which reconstructs 3D images from 2D electron microscope images for nanometer-sized crystals in a metal hydrate, for analysis. As a result, they showed that the metastable phase was thermodynamically stable, identified the 3D structure of metastable phase crystals and suggested a novel growth mechanism for nanoparticles called ‘multistage crystallization’. This study is important because it reveals a new paradigm in metastable phase materials development, when most research is focused on developing stable phase materials.

Development of metastable phase advanced material synthesis technology

3D atomic structure of metastable palladium hydride nanoparticles as identified by atomic electron tomography and a scheme of the growth process of nanoparticles in metastable phase. Credit: Korea Institute of Science and Technology

dr. Chun said: “These research results provide an important process to gain source technology in the development of advanced alloy materials containing lightweight atoms. Additional research is expected to reveal a new paradigm in the development of metastable phase-based environmentally friendly energy materials capable of producing hydrogen and lithium. Like the Czochralski (CZ) method, which is used to produce monocrystalline silicon, an important material in today’s semiconductor industry, it will be a source technology with great potential that will contribute to advanced material development.”


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More information:
Jaeyoung Hong et al, Metastable hexagonal densely packed palladium hydride in liquid cell TEM, Nature (2022). DOI: 10.1038/s41586-021-04391-5

Provided by the National Research Council of Science & Technology

Quote: Development of Metastable Phase Advanced Material Synthesis Technology (2022, April 15) Retrieved April 15, 2022 from https://phys.org/news/2022-04-metastable-phase-advanced-material-synthesis-technology.html

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