ChemRxiv
These are preliminary reports that have not been peer-reviewed. They should not be regarded as conclusive, guide clinical practice/health-related behavior, or be reported in news media as established information. For more information, please see our FAQs.
1/1
0/0

Unveiling Pseudocapacitive Charge Storage Behavior in FeWO4 Electrode Material by Operando X-ray Absorption Spectroscopy

preprint
submitted on 07.12.2019 and posted on 16.12.2019 by Nicolas Goubard-Bretesché, Olivier Crosnier, Camille Douard, Antonella Iadecola, Richard Retoux, Christophe Payen, Marie-Liesse Doublet, Kazuaki Kisu, Etsuro Iwama, Katsuhiko Naoi, Frédéric Favier, Thierry Brousse
In nano-sized FeWO4 electrode material, both Fe and W metal cations are suspected to be involved in the fast and reversible Faradaic surface reactions giving rise to its pseudocapacitive signature. As for any other pseudocapacitive materials, to fully understand the charge storage mechanism, a deeper insight into the involvement of the electroactive cations still has to be provided. The present paper illustrates how operando X-ray absorption spectroscopy (XAS) has been successfully used to collect data of unprecedented quality allowing to elucidate the complex electrochemical behavior of this multicationic pseudocapacitive material. Moreover, these in-depth experiments were obtained in real time upon cycling the electrode, which allowed investigating the reactions occurring in the material within a realistic timescale, which is compatible with electrochemical capacitors practical operation. Both Fe K-edge and W L3-edge measurements point out the involvement of the Fe3+/Fe2+ redox couple in the charge storage while W6+ acts as a spectator cation. The result of this study enables to unambiguously discriminate between the Faradaic and capacitive behavior of FeWO4. Beside these valuable insights toward the full description of the charge storage mechanism in FeWO4, this paper demonstrates the potential of operando X-ray absorption spectroscopy to enable a better material engineering for new high capacitance pseudocapacitive electrode materials.

Funding

ANR-15-CE05-0011-01

ANR-10-LABX-76-01

Global Innovation Research Organization in TUAT

ANR-10-EQPX-45

History

Email Address of Submitting Author

nicolas.goubardb@gmail.com

Institution

Institut des Matériaux Jean Rouxel (IMN), CNRS UMR 6502 – Université de Nantes, Nantes, France

Country

France

ORCID For Submitting Author

0000-0001-8236-821X

Declaration of Conflict of Interest

The authors have no conflict of interest to declare.

Exports