Improving Mg2+ ionic conductivity in ZIF-8 by Cu (II) doping and mbIm incorporation into the framework

• Published in: Solid state ionics Vol. 407; p. 116497
• Main Authors: Sánchez, L., Acevedo-Peña, P., Aguilar-Frutis, Miguel Á., Reguera, E.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.04.2024
• Subjects: Electrochemical impedance spectroscopy; Ionic conductivity; Mg-ion battery; Solid electrolyte; ZIF; Mg-ion battery; ZIF; Solid electrolyte; Ionic conductivity; Electrochemical impedance spectroscopy
• ISSN: 0167-2738; 1872-7689
• DOI: 10.1016/j.ssi.2024.116497

Transitioning to all-solid-state batteries and alternative technologies from liquid electrolyte counterparts is a matter of security and sustainability. In this scenario, magnesium is a strong candidate to replace lithium as a charge carrier because of its vast abundance, higher energy density, and suitability to be loaded in solid-state electrolytes, making batteries safer. This contribution reports a new solid electrolyte based on ZIF-8 modifications to improve its ionic conductivity. That material was obtained by the precipitation method and characterized through various spectroscopic and microscopic approaches. The ZIF-8 was modified by partially substituting the metal center, partially replacing Zn(II) with Cu(II), or the organic ligand, changing a fraction of 2-Methylimidazole with 2-Methylbenzimidazole. The impact of these modifications on the pristine ZIF-8 performance as an ionic conductor is tested through electrochemical impedance spectroscopy measurements, achieving a promising room-temperature ionic conductivity of 1 μS/cm. This work represents an effort to find a solid electrolyte synthesized under mild conditions with high conductivity to build a functional magnesium-ion battery prototype. Transport of Mg2+ in functionalized Zn imidazole as a solid electrolyte for potential Mg2+- based batteries. That material was functionalized by replacing a fraction of Zn atoms with Cu(2+) atoms, and of methylimidazole by benzimidazole. [Display omitted] •Solid state electrolytes.•Mg ion-based battery.•Modified Zn methylimidazolate.•MOF-based solid electrolyte.•Mg ion mobility in modified ZIF-8.