An Assessment of FeOF as Cathode Material for Fluoride-Ion Batteries

Expanding the Horizons of Sustainable Energy Storage

Master thesis (2023)

Authors

P.J.M. Breed Mechanical Engineering

Contributors

P. Braga Groszewicz RST/Storage of Electrochemical Energy - AS (supervisor 1)
Y. Gonzalez Garcia Team Yaiza Gonzalez Garcia - Mechanical, Maritime and Materials Engineering (supervisor 1)
Faculty
Mechanical Engineering
Copyright: © 2023 Paul Breed
Electrochemical cell Fluoride-ion battery Iron oxyfluoride Ferrous oxide Electrode material
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Published Date

24-07-2023

Language

English

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Faculty

Mechanical Engineering

Abstract

This study aims to assess the suitability of iron oxyfluoride (FeOF) as cathode material for fluoride-ion batteries based on the electrochemical performance and fluorination capability of ferrous oxide (FeO), as well as the defluorination of FeOF. Due to the pressing demand for electrochemical storage, alternatives to the widespread lithium-ion battery must be sought. One alternative can be the fluoride-ion battery (FIB). By trying to combine the stability of intercalation-based electrode materials and the high energy density of conversion-based materials, oxyfluorides might be the answer, especially if based on an abundant transition metal such as iron. In this report, the suitability of iron oxyfluoride as cathode material was evaluated. This was done by synthesising the electrode composites, evaluating their performance in a custom-made electrochemical cell and investigating the phase transitions of the researched materials. It was found that the ferrous oxide could not be fluorinated in an electrochemical environment and only reached a capacity of 0.75 mAh/g, which is equal to 0.2% of the theoretical capacity. It was also found that the iron oxyfluoride could not be electrochemically defluorinated. Therefore it is concluded that iron oxyfluoride is not suitable as cathode material for fluoride ion batteries.