Two-dimensional MXenes for energy storage and conversion applications

An emerging family of layered early transition metal carbides and/or nitrides-MXenes-has been intensively investigated by both theoretical calculations and experimental research to explore their unique properties and potential applications. The two-dimensional film morphology coupled with a fascinating combination of metallic conductivity and the hydrophilic nature of their functionalized surface render them as promising candidates for a wide range of utilizations. This article reviews recent advances on MXenes and their composites with either polymers or small molecules. Their wet chemistry and structural characterization are first described. Then we discuss in detail their numerous applications of energy storage and conversion including supercapacitors, batteries and thermoelectric devices. In particular, their electrochemical and thermoelectric properties, performances and mechanisms are presented with regard to their respective structures, compositions and fabrication methods. Finally, a conclusion of recent progress on MXenes is made with a perspective for their possible future directions. (c) 2017 Elsevier Ltd. All rights reserved.