3D MXene Architectures for Efficient Energy Storage and Conversion

Abstract

2D transition metal carbides and/or nitrides (MXenes), by virtue of high electrical conductivity, abundant surface functional groups and excellent dispersion in various solvents, are attracting increasing attention and showing competitive performance in energy storage and conversion applications. However, like other 2D materials, MXene nanosheets incline to stack together via van der Waals interactions, which lead to limited number of active sites, sluggish ionic kinetics, and finally ordinary performance of MXene materials/devices. Constructing 2D MXene nanosheets into 3D architectures has been proven to be an effective strategy to reduce restacking, thus providing larger specific surface area, higher porosity, and shorter ion and mass transport distance over normal 1D and 2D structures. In this review, the commonly used strategies for manufacturing 3D MXene architectures (3D MXenes and 3D MXene-based composites) are summarized, such as template, assembly, 3D printing, and other methods. Special attention is also given to the structure-property relationships of 3D MXene architectures and their applications in electrochemical energy storage and conversion, including supercapacitors, rechargeable batteries, and electrocatalysis. Finally, the authors propose a brief perspective on future opportunities and challenges for 3D MXene architectures/devices.

Strongly Coupled 2D Transition Metal Chalcogenide-MXene-Carbonaceous Nanoribbon Heterostructures with Ultrafast Ion Transport for Boosting Sodium/Potassium Ions Storage

“…Nevertheless, the deficiencies of easy self-aggregation, unsatisfying ions accessibility, and low theoretical capacity are generally inevitable for MXenes, because of the hydrogen bonds or van der Walls interactions between the laminated adjacent layers. Particularly, the performance is yet far to be satisfied when used as the anode of the batteries with larger alkali-metal ions [ 3 , 11 ]. It is thus requested the design of advanced heterostructures to address the above-mentioned challenges in the electrochemical energy storage applications [ 12 , 13 ].…”

Intercalation as a versatile tool for fabrication, property tuning, and phase transitions in 2D materials

“…Intercalation can also be used in the fabrication of supercapacitors, between MXenes and the intercalants. MXenes, which are generally prepared from MAX phases comprised of layered ternary carbides with the formula is M n+1 X n T z (n is an integer between 1 and 4) [133][134][135][136] where M is an early transition metal, X is carbon and/or nitrogen, and T embodies various terminations such as fluorine, hydroxyl, and/or oxygen atoms 120,121 . Shen et al 137 reported improved electrical conductivity and electrochemical performance when carbon-intercalated Ti 3 C 2 T x MXene (Ti 3 C 2 T x /C) was used as the active electrode material of supercapacitors.…”

MXenes for Solar Cells

“…The newly reported electrical conductivity of the Ti 3 C 2 T x MXene has reached as high as 15,100 S cm –1 [ 66 ], and moreover, high transparency, outstanding flexibility and adjustable WF are associated with it [ 67 – 69 ]. All these properties make Ti 3 C 2 T x suitable as electrodes in optoelectronic devices including solar cells.…”