ABSTRACT

Basic Information

Abstract Number: 1640 - 7
Author Name: Majid Beidaghi - Drexel University
Session Title: Nanoelectrochemistry of Energy Conversion and Storage
Event Type: Symposia
Event Title: Mechanisms of Electrochemical Charge Storage in Two-Dimensional Ti3C2 MXene

Presider Name:Michael V MirkinCo-Author:Maria Lukatskaya, Yury Gogotski, Michel W Barsoum, Mikhael D Levi, Doron Aurbach
Affiliation:CUNY, Queens CollegeAffiliation:Drexel University, Bar-Ilan University

Date: Wednesday, March 11, 2015
Start Time: 11:10 AM (Slot #7)
Location: 260

Abstract Content

MXenes, a recently discovered large family of two-dimensional (2D) early transition metal carbides and carbonitrides, have shown much promise in electrochemical energy storage applications, such as battery and supercapacitor electrodes. We recently reported on large volumetric capacitance and high rate capabilitiy of Ti3C2Tx – the most studied MXene to date. Spontaneous intercalation of a variety of single- and multiply charged cations, together with highly reversible electrochemical insertion of the same cations, has been well documented for Ti3C2Tx in aqueous electrolytes. Perfect capacitive behavior was observed for Ti3C2Tx MXene even at quite high charge and discharge rates, contradicting to slow intercalation of ions in a specific potential range, which is usually observed in layered materials for battery applications.

In order to understand mechanism of capacitance in MXenes we performed characterization of the mechanical deformations of MXene electrode materials at various states-of-charge with a variety of cations (Li, Na, K, Cs, Mg, Ca, Ba, and three tetra¬alkylammonium cations) during cycling by electrochemical quartz-crystal admittance (EQCA, quartz-crystal microbalance with dissipation monitoring) combined with in situ electronic conductance and electrochemical impedance. Based on this work, it appears that in MXenes cationic insertion is accompanied by significant deformation of the Ti3C2Tx particles, that occurs so rapidly so as to resemble 2D ion adsorption at solid-liquid interfaces. The latter is greatly facilitated by the presence of water molecules between the MXene sheets.