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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Translating Fundamental Insights into Ag-Based Bimetallic Electrocatalysts to Anion-Exchange Membrane Fuel Cells

To address challenges of high costs and scalability for fuel cells, it is essential to develop af-fordable and earth-abundant materials that are Pt-group-metal (PGM)-free. Recent advance-ments in PGM-free electrocatalysis for the oxygen reduction reaction (ORR) in alkaline media show that high catalyst loadings are needed to achieve high reaction rates; however, there are associated mass transport limitations. To address this issue, we develop low-loading ionomer-less Ag-bimetallic thin films by alloying with 3d block elements or Sn. We bridge knowledge from fundamental rotating disk electrode (RDE) studies to gas-diffusion cathodes in high-temperature anion-exchange membrane fuel cells (HT-AEMFCs), resulting in high-activity ORR catalysis and peak power densities up to 1.2 W cm-² geo for the Ag-Sn and Ag-Co alloys. Here, experimental post-characterization and theoretical calculations reveal small Co or Sn oxide nano-islands on Ag as likely active sites enhancing ORR activity, ultimately offering these low-loading PGM-free ORR materials as a viable path towards sustainable energy conversion.

Catalysts↗
DOE OSTI2024

On the mechanisms of J c increment and degradation in high- J c Ba122 tapes made by different processing methods

We compared the grain and grain boundary (GB) nanostructures in two Ba122 tapes with similarly high J c . The Ag-sheathed tape made by hot pressing has larger, more plate-like grains with better c-axis alignment but has more GBs blocked by FeAs and Ba–O. In contrast, the tape made by cold pressing with an Ag-Sn/stainless steel sheath possesses fewer plate-like grains and weaker grain alignment but has more continuous current paths with clean physically well-connected GBs. Our nanostructural comparison emphasizes the strong need to achieve both good grain alignment and clean GBs for further J c improvement of Ba122 tapes.

Kametani, F.↗
DOE OSTI2020

Materials Data on Ag3Sn by Materials Project

Ag3Sn is beta Cu3Ti structured and crystallizes in the orthorhombic Pmmn space group. The structure is three-dimensional. there are two inequivalent Ag sites. In the first Ag site, Ag is bonded to eight Ag and four equivalent Sn atoms to form AgAg8Sn4 cuboctahedra that share corners with four equivalent SnAg12 cuboctahedra, corners with fourteen AgAg8Sn4 cuboctahedra, edges with six equivalent SnAg12 cuboctahedra, edges with twelve AgAg8Sn4 cuboctahedra, faces with four equivalent SnAg12 cuboctahedra, and faces with sixteen AgAg8Sn4 cuboctahedra. There are a spread of Ag–Ag bond distances ranging from 2.99–3.09 Å. There are three shorter (3.02 Å) and one longer (3.07 Å) Ag–Sn bond lengths. In the second Ag site, Ag is bonded to eight equivalent Ag and four equivalent Sn atoms to form AgAg8Sn4 cuboctahedra that share corners with eight equivalent SnAg12 cuboctahedra, corners with ten AgAg8Sn4 cuboctahedra, edges with eighteen AgAg8Sn4 cuboctahedra, faces with six equivalent SnAg12 cuboctahedra, and faces with fourteen AgAg8Sn4 cuboctahedra. There are two shorter (2.99 Å) and two longer (3.06 Å) Ag–Sn bond lengths. Sn is bonded to twelve Ag atoms to form SnAg12 cuboctahedra that share corners with two equivalent SnAg12 cuboctahedra, corners with sixteen AgAg8Sn4 cuboctahedra, edges with six equivalent SnAg12 cuboctahedra, edges with twelve equivalent AgAg8Sn4 cuboctahedra, faces with six equivalent SnAg12 cuboctahedra, and faces with fourteen AgAg8Sn4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ag3Sn by Materials Project

Ag3Sn is Magnesium-derived structured and crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. there are two inequivalent Ag sites. In the first Ag site, Ag is bonded to twelve Ag atoms to form AgAg12 cuboctahedra that share corners with six equivalent AgAg12 cuboctahedra, corners with twelve equivalent SnAg6Sn6 cuboctahedra, edges with eighteen AgAg12 cuboctahedra, faces with two equivalent SnAg6Sn6 cuboctahedra, and faces with eighteen AgAg12 cuboctahedra. There are six shorter (2.93 Å) and six longer (3.11 Å) Ag–Ag bond lengths. In the second Ag site, Ag is bonded to nine Ag and three equivalent Sn atoms to form AgAg9Sn3 cuboctahedra that share corners with eighteen equivalent AgAg9Sn3 cuboctahedra, edges with six equivalent SnAg6Sn6 cuboctahedra, edges with twelve AgAg12 cuboctahedra, faces with six equivalent SnAg6Sn6 cuboctahedra, and faces with fourteen AgAg12 cuboctahedra. All Ag–Ag bond lengths are 3.11 Å. All Ag–Sn bond lengths are 3.10 Å. Sn is bonded to six equivalent Ag and six equivalent Sn atoms to form SnAg6Sn6 cuboctahedra that share corners with six equivalent SnAg6Sn6 cuboctahedra, corners with twelve equivalent AgAg12 cuboctahedra, edges with six equivalent SnAg6Sn6 cuboctahedra, edges with twelve equivalent AgAg9Sn3 cuboctahedra, faces with six equivalent SnAg6Sn6 cuboctahedra, and faces with fourteen AgAg12 cuboctahedra. All Sn–Sn bond lengths are 3.11 Å.

36 MATERIALS SCIENCE↗