Research Article

Advances in Sol-Gel Synthesis of MgZr4(1-x)Hf4xP6O24 (x = 0, 1) Solid Electrolytes for Electrochemical Devices

Mohammed Alhaji Adamu1*, Girish M Kale2
1 Kog State Polytechnic Lokoja
2 School of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom
* Corresponding author: drmadamu@yahoo.com
Published: Jul, 2025
Pages: 7-17

Abstract

The potential solid electrolytes, MgZr4P6O24 and MgHf4P6O24 were prepared using modified novel sol-gel method. Structural and electrical properties of the solid electrolytes were determined. TGA-DSC analyses indicated that the pure dried xerogel powders, when calcined at 900 oC converts to pure single phase MgZr4P6O24 and MgHf4P6O24 nanopowders with excellent crystallinity. Pellets of 13 mm diameter and 3.8 mm thickness made by uniaxial compression were respectively sintered at 1300 oC. Powder XRD analyses indicated that crystalline phase of MgZr4P6O24 and MgHf4P6O24 nanoparticles exhibit monoclinic structure with crystallite size of approx. 39 mm and 42 mm, respectively. The sintered pellets were stable from 1000 oC to 1300 oC, with MgHf4P6O24 solid electrolyte showing no trace of coexistent second phase at higher temperatures. Relative density analyses of sintered MgZr4P6O24 and MgHf4P6O24 pellets yield optimum density of approx. 99% and 98% at 1300 oC, respectively, which are in perfect agreement with SEM-EDS analyses of the sintered pellets. Using impedance spectroscopy, the bulk ionic conductivity of the platinum-cured sintered MgZr4P6O24 and MgHf4P6O24 pellets were determined as 7.23 x 10-3 Scm-1 at 725 oC and 4.52 x 10-4 Scm-1 at 747 oC, respectively. Activation energy of MgZr4P6O24 (Ea = 0.84±0.04eV) and  gHf4P6O24 (Ea = 0.74±0.02eV) solid electrolytes indicating MgZr4P6O24 solid electrolyte as possessing improved Mg2+-ion conducting mobile species at high temperatures. However, both solid electrolytes find suitable applications in electrochemical devices.

Keywords

Sol-gel synthesis Solid electrolyte MgZr4(1-x)Hf4xP6O24 Structural analysis Electrical Properties Electrochemical devices

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How to Cite

Adamu, M. A., & Kale, G. M. (2025). Advances in Sol-Gel Synthesis of MgZr4(1-x)Hf4xP6O24 (x = 0, 1) Solid Electrolytes for Electrochemical Devices. Nigerian Journal of Materials Science and Engineering, 15(1), 7-17.

M. A. Adamu, and G. M. Kale, "Advances in Sol-Gel Synthesis of MgZr4(1-x)Hf4xP6O24 (x = 0, 1) Solid Electrolytes for Electrochemical Devices," Nigerian Journal of Materials Science and Engineering, vol. 15, no. 1, pp. 7-17, July 2025.

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