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Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - SynFoNY (Synthesis and Formulation of Nanoparticles for pinning in YBCO coated conductors)

Teaser

Summary

People\'s concern about global warming and the rapid growth of the world population has prompted scientists to develop renewable electrical energy and to find new technologies with a minimum of carbon dioxide emissions. High-temperature superconducting technologies have the potential to transport electricity without resistance. However, the implementation of these high-temperature superconductors in power applications is constrained due to the presence and movement of vortices in the presence of a medium to high magnetic field. In this project, we focused on the improvement of the superconducting YBa2Cu3O7-Î´ (YBCO) properties by immobilizing the vortices via the incorporation of preformed double metal oxide nanocrystals as artificial pinning centers in the YBCO matrix. The chemical solution deposition approach was introduced to synthesize the high-quality superconducting nanocomposite thin films starting from nano-suspensions for the implementation of the YBCO coated conductors throughout the energy market.

Both industrial (BASF SE, HTE GmbH, d-Nano GmbH) and academic partners (Ghent University, University of Turku) will be working on the development and fundamental understanding of new ink formulations for industrial superconductor production. The project named SynFoNY (Synthesis & Formulation for Nanoparticle pinning in YBCO) will be supported by a European Industrial Doctorate grant, started in early 2017, and is set to enable the broader use of YBCO superconductors in a variety of challenging applications, such as generators for wind turbines.

These are the objectives of SynFoNY:
(1) Training of two ESRs on different technical and industrial aspects:
- Research objective for ESR1: Industrial synthesis, formulation and incorporation of preformed bimetallic nanocrystals in YBCO precursor solutions for the development of superconducting nanocomposites.
- Research objective for ESR2: product and process development of industrial scaled deposition of superconducting nanocomposite architectures and their in-depth microstructural and physical characterization.
(2) The scalable development of nanocomposite architectures with tunable properties.

Work performed

In the beginning of the project, the preparation of bimetallic alkoxide precursors (WP1) was investigated to deliver series of bimetallic alkoxide precursors. These alkoxide precursors show good miscibility/solubility in benzyl alcohol which is ideal for the nanocrystal synthesis method. During the nanocrystal synthesis method, benzyl alcohol (non-toxic) will used as the solvent-controlled non-aqueous routes to metal oxide nanocrystals as it can offer a good accessibility to nanocrystal\'s surface.

For the WP2, we already introduced some design of experiments to synthesize double metal oxide nanocrystals via the microwave-assisted synthesis. To obtain colloidally stable double metal oxide nanocrystals, we introduce the solvothermal microwave-assisted synthesis starting from different types of bimetallic precursors. In this microwave procedure, small nanocrystals with the cubic crystal phase are obtained after the synthesis. The double metal oxide nanocrystals are agglomerated directly after microwave synthesis but can be de-agglomerated via a post-functionalization step (WP3) with carboxylate ligands, providing stabilization via steric hindrance in an apolar solvent such as toluene. These particles can be also stabilized with copolymer (containing phosphonate group) to have a colloidally nanosuspension in polar solvent like methanol.This microwave-assisted method also delivers an advantage to tune the crystal size depending on the used bimetallic precursors and lies between 3 and 6.5 nm. This results in a larger applicability of double metal oxide nanocrystals as artificial pinning centers. The microwave-assisted synthesis starting from bimetallic percursors show some promising results and should be further optimized to have desired properties.

In WP4, the YBCO precursor solution with preformed nanocrystals was deposited on LaAlO3 substrate (Lab scale) via chemical solution deposition approach to study the growth mechanism of YBCO nanocomposite film. After this deposition and its thermal treatment, we achieved good (00â„“)-texture of YBCO with good critical current densities but did not exhibit improved pinning properties, indicating the double metal oxide nanocrystals are pushed to the YBCO surface or settled on the YBCO/LaAlO3 interface during the YBCO growth. For this reason, a further research will be required to understand the behavior of preformed nanocrystals during the formation of superconducting YBCO nanocomposite film.

Final results

Nanocrystal reinforced YBCO inks will open the door for High-Temperature superconducting magnetic high field applications like motors for ship propulsion or generators for wind turbines. Focusing the expertise in the areas of synthesis, formulation, engineering and analytics will facilitate the challenging milestone delivery.
The candidates will not only take part in creating these new materials on the lab scale, but also be able to contribute to finding a new way of tuning the properties of nano-sized ceramic particles in a scalable flow process. Controlling the size, surface chemistry and agglomeration as well as the chemical composition of these systems will create benefits for the development of the three large types of nanomaterials, i.e. dielectrics, semiconductors and conductors. It will also make their processing safer and more sustainable.