Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Sodium Superionic Conduction in Na2B12H12

Published

Author(s)

Terrence J. Udovic, Matoaki Matsuo, Atsushi Unemoto, Kristina Verdal, Vitalie Stavila, Alexander V. Skripov, John J. Rush, Hitoshi Takamura, Shin-Ichi Orimo

Abstract

The need for cheaper, Li-free battery technologies has prompted the search for new Na-ion-based electrolyte materials. One such material, Na2B12H12, undergoes an entropy-driven transition upon heating from an ordered monoclinic structure to a disordered cubic structure at around 529 K. Impedance measurements across the phase transition have indicated a nearly three-orders-of-magnitude jump in Na+ cation conductivity, approaching 0.1 S/cm. The unusually high cation mobility above the transition is a result of the "melting" of the Na+ cation sublattice within the body-centered-cubic (bcc)arrangement of the orientationally disordered B12H122- anions, similar to what is observed for the mobile Ag+ sublattice in the bcc phase of AgI. The high reorientational mobility, relatively large size, and quasispherical shape of the B12H122- anions may all play roles in facilitating Na+ diffusion. Superionicity, high-temperature stability, and low cost combine to make Na2B12H12 an attractive solid-state electrolyte for future Na-based batteries. It is probably that even better properties, i.e., lower phase-transition temperatures and higher ion conduction, can be realized, eg.g., via modification or subsitiution of the B12H122+ anions.
Citation
Chemical Communications
Volume
50

Keywords

battery, cation vacancy, complex hydride, conductivity, impedance measurement, ion conductivity, Na cation, sodium, superionicity

Citation

Udovic, T. , Matsuo, M. , Unemoto, A. , , K. , Stavila, V. , , A. , Kasianowicz, J. , Takamura, H. and Orimo, S. (2014), Sodium Superionic Conduction in Na<sub>2</sub>B<sub>12</sub>H<sub>12</sub>, Chemical Communications, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=915272 (Accessed March 28, 2024)
Created April 11, 2014, Updated February 19, 2017