Applications of 2D MXenes for Electrochemical Energy Conversion and Storage

Abstract

As newly emerged 2D layered transition metal carbides or carbonitrides, MXenes have attracted growing attention in energy conversion and storage applications due to their exceptional high electronic conductivity, ample functional groups (e.g., -OH, -F, -O), desirable hydrophilicity, and superior dispersibility in aqueous solutions. The significant advantages of MXenes enable them to be intriguing structural units to engineer advanced MXene-based nanocomposites for electrochemical storage devices with remarkable performances. Herein, this review summarizes the current advances of MXene-based materials for energy storage (e.g., supercapacitors, lithium ion batteries, and zinc ion storage devices), in which the fabrication routes and the special functions of MXenes for electrode materials, conductive matrix, surface modification, heteroatom doping, crumpling, and protective layer to prevent dendrite growth are highlighted. Additionally, given that MXene are versatile for self-assembling into specific configuration with geometric flexibility, great efforts about methodologies (e.g., vacuum filtration, mask-assisted filtration, screen printing, extrusion printing technique, and directly writing) of patterned MXene-based composite film or MXene-based conductive ink for fabricating more types of energy storage device were also discussed. Finally, the existing challenges and prospects of MXene-based materials and growing trend for further energy storage devices are also presented.

MXene-Based Nanocomposites for Piezoelectric and Triboelectric Energy Harvesting Applications

“…MXenes have several mechanical characteristics, which is highly suitable for energy harvesting applications [ 162 ]. MXenes have a high Young’s modulus, which indicates their ability to resist deformation under stress with high tensile strength, which resembles those properties resisting fracture under tensile condition [ 163 ].…”

Recent developments in 2D materials for energy harvesting applications

“…Graphene: Reprinted from [69], Copyright (2010), with permission from Elsevier. MXene: Reproduced from [50]. CC BY 4.0.…”

“…Tuning the chemistry and structure of 2D materials allows easy control over their properties to impart high performance to the device. The family of 2D materials includes TMDs, graphene, graphene oxide (GO), BP, metal-or covalent-organic frameworks (MOFs/COFs), MXenes and hexagonal boron nitride (h-BN) (figure 1) [48,[50][51][52][53]. For TENGs, 2D materials can serve as electrodes, active triboelectric layers or both.…”

Current Trends and Promising Electrode Materials in Micro-Supercapacitor Printing

“…Due to their layered structure, high electrical conductivity, and huge variation in composition (which allows its optimization for a specific task), MXenes are recognized as very promising component base for various modern devices, e.g., in sensorics [ 163 , 164 , 165 , 166 , 167 ], catalysis [ 168 , 169 ], industrial water purification [ 170 , 171 ], and the creation of electrodes that often retain high energy density at high current densities [ 172 ]. However, they are of the greatest interest as components of energy generation and storage devices—lithium/sodium-ion batteries and supercapacitors [ 173 , 174 , 175 , 176 , 177 ]—especially owing to the possibility of intercalation of various ions into the interlayer space and high hydrophilicity of surface groups. An attractive aspect for the development of portable and implantable devices (similar to e-textile or electronic-tattoo) based on MXene is their antibacterial activity and mechanical elasticity of the layers, as established in several studies [ 178 , 179 ].…”