Rb2Ti2O5 : a layered ionic conductor at the sub-micrometer scale

TL;DR

This paper investigates the electrical properties of layered Rb2Ti2O5 at the sub-micrometer scale, revealing its potential as a superionic conductor with stable ionic conductivity suitable for energy storage applications.

Contribution

It provides the first detailed study of Rb2Ti2O5's electrical properties at the nanoscale, combining micro-Raman, AFM, and electrical measurements on exfoliated nanocrystals.

Findings

RTO nanocrystals exhibit superionic conduction.

Electrical properties are consistent across nano- and macro-scale samples.

RTO shows promise for energy storage applications.

Abstract

Over the past few years, ionic conductors have gained a lot of attention given the possibility to implement them in various applications such as supercapacitors, batteries or fuel cells as well as for resistive memories. Especially, layered two-dimensional (2D) crystals such as h-BN, graphene oxide and MoSe2 have shown to provide unique properties originating from the specific 2D confinement of moving ions. Two important parameters are the ion conductivity and the chemical stability over a wide range of operating conditions. In this vein, Rb2Ti2O5 has been recently found displaying remarkable properties such as superionic conduction and colossal equivalent dielectric constant. Here, a first approach to the study of the electrical properties of layered Rb2Ti2O5 at the 100-nanometer scale is presented. Characterizations by means of micro-Raman spectroscopy and atomic force microscope (AFM) measurements of mechanically exfoliated RTO nanocrystals via the so-called adhesive-tape technique are reported. Finally, the results of electrical measurements performed on an exfoliated RTO nanocrystals are presented, and are found to be consistent with the results obtained on macroscopic crystals. 4