Recently a new, large family of two-dimensional (2D) early transition metal carbides and carbonitrides, called MXenes, was discovered. MXenes are produced by selective etching of the A element from the MAX phases, which are metallically conductive, layered solids connected by strong metallic, ionic, and covalent bonds, such as Ti2AlC, Ti3AlC2, and Ta4AlC3. MXenes ­combine the metallic conductivity of transition metal carbides with the hydrophilic nature of their hydroxyl or oxygen terminated surfaces. In essence, they behave as “conductive clays”. This article reviews progress—both ­experimental and theoretical—on their synthesis, structure, properties, intercalation, delamination, and potential applications. MXenes are expected to be good candidates for a host of applications. They have already shown promising performance in electrochemical energy storage systems. A detailed outlook for future research on MXenes is also presented.

25th Anniversary Article: MXenes: A New Family of Two‐Dimensional Materials

http://ieeexplore.ieee.org/iel5/5610941/5624686/05624745.pdf

Power electronics

http://liu.diva-portal.org/smash/get/diva2:303552/FULLTEXT01

The Mn+1AXn phases: Materials science and thin-film processing

The MAX phases are a group of layered ternary compounds with the general formula Mn+1AXn (M: early transition metal; A: group A element; X: C and/or N; n = 1–3), which combine some properties of metals, such as good electrical and thermal conductivity, machinability, low hardness, thermal shock resistance and damage tolerance, with those of ceramics, such as high elastic moduli, high temperature strength, and oxidation and corrosion resistance. The publication of papers on the MAX phases has shown an almost exponential increase in the past decade. The existence of further MAX phases has been reported or proposed. In addition to surveying this activity, the synthesis of MAX phases in the forms of bulk, films and powders is reviewed, together with their physical, mechanical and corrosion/oxidation properties. Recent research and development has revealed potential for the practical application of the MAX phases (particularly using the pressureless sintering and physical vapour deposition coating rout...

Progress in research and development on MAX phases: a family of layered ternary compounds

Since their inception in 2011, from the inaugural synthesis of multi-layered Ti3C2Tx by etching Ti3AlC2 with hydrofluoric acid (HF), novel routes with a myriad of reducing agents, etchants and intercalants have been explored and many new members have been added to the two-dimensional (2D) material constellation. Despite being endowed with the rare combination of good electronic conductivity and hydrophilicity, their inherent low capacities, for instance, temper their prospect for application for electrodes in energy storage systems. MXene-based composites, however, with a probable synergistic effect in agglomeration prevention, facilitating electronic conductivity, improving electrochemical stability, enhancing pseudocapacitance and minimizing the shortcomings of individual components, exceed the previously mentioned capacitance ceiling. In this review, we summarise the development and progress in the synthesis of various multi-layered carbides, carbonitrides and nitrides, and intercalants, as well as the subsequent processing in order to delaminate them into single- and/or few-layered and incorporate into MXene-based composites, focusing on their performance and application as transparent conductive films, environmental remediation, electromagnetic interference (EMI) absorption and shielding, electrocatalysts, Li-ion batteries (LIBs), supercapacitors and other electrochemical storage systems.

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J. Y. Wang

Papers

High-temperature oxidation and hot corrosion of Cr2AlC

Strengthening of Ti2AlC by substituting Ti with V

Structure stability of Ti3AlC2 in Cu and microstructure evolution of Cu-Ti3AlC2 composites

Mechanical properties and atomistic deformation mechanism of γ-Y2Si2O7 from first-principles investigations

Influence of water vapor on the oxidation behavior of Ti3AlC2 and Ti2AlC