EAGER: CAS-Climate: Revitalizing Iron Hydroxide Electrode for Energy-Efficient Green Batteries by Promoting Ferrous- and Ferric- Hydroxides Redox

Worcester Polytechnic Institute, Worcester MA

Investigators

Abstract

In this project, funded by the Chemical Structure, Dynamics & Mechanisms B Program of the Chemistry Division, Professor Xiaowei Teng of the Department of Chemical Engineering at Worcester Polytechnic Institute is developing new classes of iron hydroxide layered materials with interesting redox properties. This research aims to exploit the characteristics of iron hydroxide layered materials, which can be used as the anode in iron-nickel alkaline batteries or iron-air alkaline batteries. The project lies at the interface of inorganic material, materials chemistry, and energy storage and is therefore well suited for the education of scientists at all levels. This project enhances education and outreach efforts by this group to increase scientific engagement and participation from underrepresented groups through a range of activities aimed at the public, high school students and teachers, undergraduate students, and graduate students. As the fourth most abundant element in the earth's crust, iron (Fe) potentially satisfies nearly all criteria for a green battery, such as various oxidation states, geographic accessibility, low cost, and environmental benefits. However, Fe anode materials face challenges in modern energy supply systems due to insufficient charging efficiency and poor discharge capability. Notably, the discharge of Fe(OH)2 forms Fe3O4, which impedes the redox process and causes cyclability loss. This project aims to probe the interplay between layered Fe(OH)2 material with anion (e.g., carbonate) and water molecules to answer the following questions: 1) how to control the local structure (e.g., structural defect) and long-range order (e.g., interlayer distance) of Fe(OH)2 materials to favor the reversible insertion and extraction of the divalent anions (carbonate)? 2) how does the anion insertion into Fe(OH)2 interlayer region impact the oxidation state of Fe species to encourage the Fe2+/Fe3+ complete conversion by FeOOH formation and discourage Fe3O4 formation? 3) how to control the interaction between Fe(OH)2, anion, and water molecules to maintain a stable layered structure during the long-term cycling? This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.