Super-tough MXene-functionalized graphene sheets

Abstract

Flexible reduced graphene oxide (rGO) sheets are being considered for applications in portable electrical devices and flexible energy storage systems. However, the poor mechanical properties and electrical conductivities of rGO sheets are limiting factors for the development of such devices. Here we use MXene (M) nanosheets to functionalize graphene oxide platelets through Ti-O-C covalent bonding to obtain MrGO sheets. A MrGO sheet was crosslinked by a conjugated molecule (1-aminopyrene-disuccinimidyl suberate, AD). The incorporation of MXene nanosheets and AD molecules reduces the voids within the graphene sheet and improves the alignment of graphene platelets, resulting in much higher compactness and high toughness. In situ Raman spectroscopy and molecular dynamics simulations reveal the synergistic interfacial interaction mechanisms of Ti-O-C covalent bonding, sliding of MXene nanosheets, and π-π bridging. Furthermore, a supercapacitor based on our super-tough MXene-functionalized graphene sheets provides a combination of energy and power densities that are high for flexible supercapacitors.

Mechanotribological Aspects of MXene‐Reinforced Nanocomposites

“…MXene's mechanical strength (≈0.33 TPa for single-layer Ti 3 C 2 T x ) is lower than graphene (≈1 TPa Young's modulus); however, it overshoots graphene oxide with the Young's modulus of ≈0.2 TPa. [93] It is worth mentioning that the mechanical performance of graphene oxide can be improved through the functionalization by MXene; [94] Zhou et al [94] achieved a tensile strength of ≈226.3 MPa and a toughness value of ≈6.2 MJ m −3 for the MXene-functionalized graphene oxides attaining, respectively 2.8 times and 6.9 times higher values compared to those obtained from the neat graphene oxide sheets. Singlelayer MXene is three times thicker than graphene and therefore has much higher bending rigidity than the other 2D nanosheets which renders MXene a great candidate for composite materials.…”

Electrical Switching of High-Performance Bioinspired Nanocellulose Nanocomposites

“…62 In comparison to integrating conductive material into the bulk of a bioinspired nanocomposite (e.g. graphene-based nacre-mimetics 63,64 ), the approach of using surface layers is more versatile as it can also be used for non-conductive bioinspired nanocomposites as shown here.…”

Anisotropic Boron–Carbon Hetero‐Nanosheets for Ultrahigh Energy Density Supercapacitors

“…Additionally, the direct chemical bonding of 1D carbon nanotubes and 2D graphene with highly conductive 3D network, sufficient contact area and unimpeded channels exhibited 2.38 times higher of capacitance when comparing with graphene [20] . Furthermore, the 2D MXene functionalized 2D graphene sheets through Ti−O−C covalent bonding could efficiently increase the electrical conductivity and mechanical property, which also led to the enhanced electrochemical performance [21] . Remarkably, this multi‐dimensional design has become an overwhelming approach to improve energy storage performance.…”

“…[20] Furthermore,t he 2D MXene functionalized 2D graphene sheets through Ti À O À Cc ovalent bonding could efficiently increase the electrical conductivity and mechanical property, which also led to the enhanced electrochemical performance. [21] Remarkably,t his multi-dimensional design has become an overwhelming approach to improve energy storage performance.H owever,t he use of such strategy to in situ manipulate 2D boron nanosheets with high conductivity and numerous channels has never been reported, which may in principle boost the energy density.…”