Reliable electrochemical phase diagrams of magnetic transition metals and related compounds from high-throughput ab initio calculations

Liang Feng Huang, James M. Rondinelli*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Magnetic transition metals (mTM = Cr, Mn, Fe, Co, and Ni) and their complex compounds (oxides, hydroxides, and oxyhydroxides) are highly important material platforms for diverse technologies, where electrochemical phase diagrams with respect to electrode potential and solution pH can be used to effectively understand their corrosion and oxidation behaviors in relevant aqueous environments. Many previous decades-old mTM–Pourbaix diagrams are inconsistent with various direct electrochemical observations, because experimental complexities associated with extracting reliable free energies of formation (ΔfG) lead to inaccuracies in the data used for modeling. Here, we develop a high-throughput simulation approach based on density-functional theory (DFT), which quickly screens structures and compounds using efficient DFT methods and calculates accurate ΔfG values, using high-level exchange-correlation functions to obtain ab initio Pourbaix diagrams in comprehensive and close agreement with various important electrochemical, geological, and biomagnetic observations reported over the last few decades. We also analyze the microscopic mechanisms governing the chemical trends among the ΔfG values and Pourbaix diagrams to further understand the electrochemical behaviors of mTM-based materials. Last, we provide probability profiles at variable electrode potential and solution pH to show quantitatively the likely coexistence of multiple-phase areas and diffuse phase boundaries.

Original languageEnglish (US)
Article number26
Journalnpj Materials Degradation
Volume3
Issue number1
DOIs
StatePublished - Dec 2019

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry
  • Materials Science (miscellaneous)
  • Chemistry (miscellaneous)

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