Solvate sponge crystals of (DMF)3NaClO4: reversible pressure/temperature controlled juicing in a melt/press-castable sodium-ion conductor

Prabhat Prakash; Shylendran Ardhra; Birane Fall; Michael J. Zdilla; Stephanie L. Wunder; Arun Venkatnathan

doi:10.1039/D0SC06455F

Solvate sponge crystals of (DMF)₃NaClO₄: reversible pressure/temperature controlled juicing in a melt/press-castable sodium-ion conductor†

Prabhat Prakash,

^ac Shylendran Ardhra,^a Birane Fall,^b Michael J. Zdilla,

*^b Stephanie L. Wunder

*^b and Arun Venkatnathan

*^a

Author affiliations

* Corresponding authors

^a Department of Chemistry and Centre for Energy Science, Indian Institute of Science Education and Research Pune, Dr Homi Bhabha Road, Pashan, Pune 411008, India
E-mail: arun@iiserpune.ac.in

^b Department of Chemistry, Temple University, 1901-N 13th St., Philadelphia, PA 19086, USA
E-mail: mzdilla@temple.edu, slwunder@temple.edu

^c Materials Science and Engineering, Indian Institute of Technology, Gandhinagar, Gujarat 382355, India

Abstract

A new type of crystalline solid, termed “solvate sponge crystal”, is presented, and the chemical basis of its properties are explained for a melt- and press-castable solid sodium ion conductor. X-ray crystallography and atomistic simulations reveal details of atomic interactions and clustering in (DMF)₃NaClO₄ and (DMF)₂NaClO₄ (DMF = N-N′-dimethylformamide). External pressure or heating results in reversible expulsion of liquid DMF from (DMF)₃NaClO₄ to generate (DMF)₂NaClO₄. The process reverses upon the release of pressure or cooling. Simulations reveal the mechanism of crystal “juicing,” as well as melting. In particular, cation–solvent clusters form a chain of octahedrally coordinated Na⁺–DMF networks, which have perchlorate ions present in a separate sublattice space in 3 : 1 stoichiometry. Upon heating and/or pressing, the Na⁺⋯DMF chains break and the replacement of a DMF molecule with a ClO₄⁻ anion per Na⁺ ion leads to the conversion of the 3 : 1 stoichiometry to a 2 : 1 stoichiometry. The simulations reveal the anisotropic nature of pressure induced stoichiometric conversion. The results provide molecular level understanding of a solvate sponge crystal with novel and desirable physical castability properties for device fabrication.

Article information

https://doi.org/10.1039/D0SC06455F

Article type

Edge Article

Submitted

24 Nov 2020

Accepted

28 Feb 2021

First published

01 Mar 2021

This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry

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Chem. Sci., 2021,12, 5574-5581

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Solvate sponge crystals of (DMF)₃NaClO₄: reversible pressure/temperature controlled juicing in a melt/press-castable sodium-ion conductor

P. Prakash, S. Ardhra, B. Fall, M. J. Zdilla, S. L. Wunder and A. Venkatnathan, Chem. Sci., 2021, 12, 5574 DOI: 10.1039/D0SC06455F

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Chemical Science