The Recent Advances in the Mechanical Properties of Self-Standing Two-Dimensional MXene-Based Nanostructures: Deep Insights into the Supercapacitor

Abstract

MXenes have emerged as promising materials for various mechanical applications due to their outstanding physicochemical merits, multilayered structures, excellent strength, flexibility, and electrical conductivity. Despite the substantial progress achieved in the rational design of MXenes nanostructures, the tutorial reviews on the mechanical properties of self-standing MXenes were not yet reported to our knowledge. Thus, it is essential to provide timely updates of the mechanical properties of MXenes, due to the explosion of publications in this filed. In pursuit of this aim, this review is dedicated to highlighting the recent advances in the rational design of self-standing MXene with unique mechanical properties for various applications. This includes elastic properties, ideal strengths, bending rigidity, adhesion, and sliding resistance theoretically as well as experimentally supported with various representative paradigms. Meanwhile, the mechanical properties of self-standing MXenes were compared with hybrid MXenes and various 2D materials. Then, the utilization of MXenes as supercapacitors for energy storage is also discussed. This review can provide a roadmap for the scientists to tailor the mechanical properties of MXene-based materials for the new generations of energy and sensor devices.

Two-Dimensional MXene Based Materials for Micro-Supercapacitors

“…Reaction (2) and (3) gives rise to the surface terminations like -O, -OH, -F etc., respectively [17,24]. MXenes have three possible structures with different layers of stacking as shown in Figure 2(b), [22] The tentative elements of MXene precursor in the periodic table predicted till now presented in Figure 2(c) [23].…”

“…HF etched highly defective MXene exhibits electronic conductivity of 1,000 Scm −1 . Whereas it improved to 4600 Scm −1 for powder and further enhanced to 6500 Scm −1 for [22] and (c) compositions of MXene elements in periodic table (Reprinted from [23]with permission from, copyright@2020, MDPI).…”

“…(a) Schematic showing the synthesis of MXene from MAX by HF treatment, (b) synthesis mechanism of different order of MXenes by MAX phases. [22] and (c) compositions of MXene elements in periodic table (Reprinted from[23]with permission from, copyright@2020, MDPI).…”

Recent Advances in Multidimensional (1D, 2D, and 3D) Composite Sensors Derived from MXene: Synthesis, Structure, Application, and Perspective

“…The synthetic approaches of MXene have been researched as an attractive issue, hence, a number of approaches have been studied. Among them, top-down approach and bottom-up method are considered as two major categories of methods, [102] such as etching from MAX or non-MAX precursors and CVD. [103,104] Generally, most MXene are synthesized by etching MAX phase in HF solution.…”

Catalytic Methane Decomposition to Carbon Nanostructures and COx-Free Hydrogen: A Mini-Review

“…Additionally, the catalysts should counterbalance the CMD activity and stability, which can be achieved by modulating the electronic effect of metal-based catalysts by alloying or forming intermetallic or core-shells with one or two more metals as well as using multiple transition metal oxides. The study of MXenes’ new classes of transition metal carbides, nitrides, or carbonitrides is among the hottest research trends nowadays; however, their gas conversion reactions are not highlighted enough relative to other energy and environmental applications [ 114 , 115 ]. Therefore, MXenes, with their unique physiochemical properties, multilayered, two-dimensional structure, and great electronic effects, could be promising catalysts for selective CMD under ambient conditions.…”