Electronic structure manipulation via composition tuning for the development of highly conductive and acid-stable oxides

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 10; no. 43; pp. 23155 - 23164
• Main Authors: Byeon, Young-Woon, Mailoa, Jonathan, Kornbluth, Mordechai, Lee, Gi-Hyeok, Cai, Zijian, Sun, Yingzhi, Yang, Wanli, Johnston, Christina, Christensen, Jake, Kim, Soo, Cheng, Lei, Kim, Haegyeom
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 08.11.2022; Royal Society of Chemistry (RSC)
• Subjects: Acidic oxides; Catalysts; Chemical composition; Corrosion; Electrical conductivity; Electrical resistivity; Electrochemistry; Electrolytic cells; Electronic structure; Energy conversion; Fuel technology; Polymers; Proton exchange membrane fuel cells; Room temperature; Stability; Titanium; Tuning; Valence
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/D2TA04084K

Exploring materials that simultaneously possess high conductivity and electrochemical stability is critical for various energy-conversion applications. In this study, our combined computations and experiments suggest the Mg–Ti–O chemical space for novel ternary oxide compounds offering high electrical conductivity and corrosion stability in acidic conditions to be potentially used as catalyst supporter of polymer electrolyte membrane fuel cells. High electrical conductivity (6.09 × 10 −1 S cm −1 ) is achieved at room temperature by tuning the chemical composition of Mg 1− x Ti 2+ x O 5 while still maintaining good corrosion stability (1.2 × 10 −4 mA cm −2 after six days) in acidic conditions. Furthermore, we discover that a reducing gas environment during the synthesis increases the Ti solubility in Mg 1− x Ti 2+ x O 5 with a reduced valence state of Ti, thus resulting in high conductivity.