New alluaudite-type Na_3.4Co_1.3(MoO₄)₃ for sodium-ion batteries and electrocatalytic hydrogen evolution

Author(s)

Mohamed Akouibaa, Brahim El Bali, Hicham Oudghiri Hassani, Nicola Morley, Tim Gruene, Mohammed Lachkar, Jack Fitzpatrick, Nuria Tapia-Ruiz, Zeliha Ertekin, Mark D. Symes

Abstract

The alluaudite-type compound Na_3.4Co_1.3(MoO₄)₃ has been successfully synthesized by a solid-state process route. It crystallizes in the monoclinic system (C2/c), cell parameters (Å,°): a = 12.582(5) Å, b = 13.449(8) Å, c = 7.119(7) Å, β = 112.02(4)°, V = 1116.8(14) Å3, and Z = 4. Its crystal structure consists of octahedral [MO₆] (M = Co, Na) and tetrahedral [MoO₄] that share corners and/or edges to build the 3D framework. The sample was also characterized by X-ray powder diffraction, which confirmed crystal data, and infrared (FT-IR) and Raman spectroscopies. Its morphology was analyzed using scanning electron microscopy (SEM). The vibrational study confirms the existence of the MoO42- functional groups. The title compound was determined to be paramagnetic. In addition, the compound was characterized by cyclic voltammetry (CV), and its electrochemical performance and impedance were analyzed by electrochemical impedance spectroscopy (EIS). The electrochemical reaction mechanism and the limiting factors of Na_3.4Co_1.3(MoO₄)₃ as electrode material in Na-ion batteries at room temperature were also discussed. The prepared electrocatalyst showed modest hydrogen evolution reaction (HER) performance with an overpotential of 309 mV required to afford a current density of 10 mA cm⁻².

Organisation(s)

Core Facility Crystal Structure Analysis, Department of Inorganic Chemistry

External organisation(s)

University Sidi Mohamed Ben Abdellah, University of Sheffield, Imperial College London, University of Glasgow

Journal

Journal of Solid State Electrochemistry

ISSN

1432-8488

DOI

https://doi.org/10.1007/s10008-025-06334-w

Publication date

2025

Peer reviewed

Yes

Austrian Fields of Science 2012

104003 Inorganic chemistry, 104005 Electrochemistry, 104024 X-ray structural analysis

Keywords

ASJC Scopus subject areas

General Materials Science, Condensed Matter Physics, Energy Engineering and Power Technology, Electrochemistry, Electrical and Electronic Engineering, Materials Chemistry

Portal url

https://ucrisportal.univie.ac.at/en/publications/3421c914-f99b-4aa0-a5e0-671b0225c0d0