Two-dimensional materials are expected to become key components for novel applications for not only electronic devices but also for energy storage applications including super capacitors and batteries because of their exotic properties.  MXenes are the newest class of two-dimensional (2D) materials, they offer a great potential in a wide range of applications including electronic devices, sensors, thermoelectric and energy storage materials. In this work, we combined the outstanding electrical conductivity, that is essential for battery applications, of graphene with MXene monolayers (M2CX2 where M=Mo, Sc, Ti, V and X=OH, O or bare) to explore its potential in ion battery applications. First, the adsorption and diffusion of Li, Na, K and Ca atoms on a Mo2C monolayer are systematically investigated by using density functional theory based calculations. We predict a significant charge transfer from the ad-atoms to the Mo2C monolayer, which indicates clearly the cationic state of the metal atoms. Then, through first principles calculations, we determined the stable stacking configurations of M2CX2/graphene bilayer heterostructures and their alkali atom intercalation by the calculating binding energy, the diffusion barrier and voltage. The adsorption and diffusion of Li, Na, K and Ca atoms on MXene/graphene heterostructures of MXene systems Sc2C(OH)2, Ti2CO2 and V2CO2 are systematically investigated by using first principles methods. We found that alkali metal intercalation is energetically favorable and thermally stable for Ti2CO2/graphene and V2CO2/graphene heterostructures but not for Sc2C(OH)2. Diffusion kinetics calculations proved the advantage of MXene/graphene heterostructures over sole MXene systems as the energy barrier values are halved at least for all considered alkali metals. Low energy barriers are found implying fast charge/discharge rate.  Given these advantages, Ti2CO2/graphene and V2CO2/graphene heterostructures are predicted to be promising for ion battery applications.<br/>

Exploring MXenes/graphene heterostructures for ion battery applications from first-principles

2019 Spring National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.