Innovative high-entropy alloys for electrochemical storage of hydrogen

• Grant number: 24/02127-2
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: January 01, 2025
• End date: April 30, 2027
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Raphael Nagao de Sousa
• Grantee: Rafael Galiza Yoshimura
• Host Institution: Instituto de Química (IQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Company: Universidade Estadual de Campinas (UNICAMP). Instituto de Química (IQ)
• Associated research grant: 17/11986-5 - Generation and storage of New Energy: bringing technological development for the country, AP.PCPE

Abstract

The electrochemical storage of hydrogen in the solid state within high-entropy alloys enables the attainment of a high volumetric energy density, as compared to available methods of hydrogen storage in liquid or compressed tanks. In addition to being an efficient and economically viable approach, it can be conducted at low temperatures and pressures, enhancing safety and operational simplicity. This doctoral research proposal aims primarily to develop and evaluate the behavior of original high-entropy alloys with a C14 Laves phase structure derived from the systems: Zr33(CrFeMnNi)67, Zr33Cr22Mn15Fe25Ni5, and (ZrCrMnFe)100-xNix for electrochemical hydrogen storage. The storage properties of these alloys will be evaluated through electrochemical tests in an alkaline solution, employing techniques such as potentiodynamic polarization, electrochemical impedance spectroscopy, galvanostatic charging, and potentiostatic discharging. Structural changes occurring in the electrodes due to hydrogenation/dehydrogenation cycles will be analyzed using Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS), and X-ray Diffraction (XRD) as well as in-situ X-ray Absorption Spectroscopy (XAS) utilizing synchrotron radiation. Furthermore, part of this thesis development involves designing spectroelectrochemical cells to optimize measurements across different techniques and gain insights into reaction mechanisms and kinetics.