MXene/N-Doped Carbon Foam with Three-Dimensional Hollow Neuron-like Architecture for Freestanding, Highly Compressible All Solid-State Supercapacitors

Abstract

Currently, the MXene-based flexible supercapacitors have caused much attention due to their excellent mechanical performance and novel electrical property. However, the aggregation and rearrangement of MXene nanosheets in the process of electrode preparation limit their electrochemical performance. Herein, a kind of novel MXene/N-doped carbon foam (MXene/ NCF) compressible composite with three-dimensional (3D) hollow interconnected neuron-like architecture is directly prepared by one-step pyrolysis and used for the freestanding, highly compressible supercapacitors. The synergistic effect exists in the MXene/ NCF composite when applied to supercapacitors: NCF can provide the additional pseudocapacitance by N atom doping and simultaneously supports the MXene nanosheets to construct the 3D hollow interconnected neuron-like architecture for supplying highly stable, efficient channels for ion diffusion/electron transport and more contact sites, and that the MXene enhances conductivity and hydrophilicity. Therefore, the freestanding MXene/NCF electrode shows a remarkable gravimetric capacitance of 332 F g −1 and volumetric capacitance of 3162 mF cm −3 , superior rate performance of 64% (from 0.5 to 100 A g −1 ), and 99.2% capacity retention after 10,000 cycles. Significantly, the MXene/NCF-based all solid-state supercapacitors still show a high specific capacitance and a large rate performance. In addition, the device can be compressed arbitrarily under 60% strain with almost no change in morphology and electrochemical property. These excellent properties expect that the MXene/NCF composite has broad applications in the field of flexible supercapacitors.

Three‐Dimensional MXenes for Supercapacitors: A Review

“…Carbon foams can be prepared via the direct pyrolysis of melamine foam, which possess 3D interconnected architecture with developed porosity, good conductivity, high surface wettability and satisfactory compressibility, and have been reported as the framework for supporting the MXene nanosheets. [ 71,72 ] Pan et al. immersed commercial melamine foam into MXene solution to be fully filled.…”

“…morphology and structure of the 3D MXene materials can be easily controlled by adjusting the supporting framework's structure. Generally, the supporting framework material should have a 3D network structure, high conductivity and good mechanical property, such as nickel foam (NF), [64][65][66][67][68] carbon cloth (CC), [69,70] carbon foam, [71,72] 3D rGO aerogel, [73] sponge, [74] etc.…”

Recent Advances in Sustainable Wearable Energy Devices with Nanoscale Materials and Macroscale Structures

“…Reproduced with permission. [ 278 ] Copyright 2020, American Chemical Society. e) Schematic illustration of the fabrication of a 3D graphene aerogel@MnO 2 electrode.…”

“…prepared an MXene@N‐doped carbon foam (NCF) composite through the direct pyrolysis of melamine sponges, as shown in Figure 18d. [ 278 ] The MXene@NCF electrodes exhibited a remarkable specific capacitance of 332 F g −1 and could be compressed at up to 60% strain with almost no reduction in the electrochemical properties. Recently, certain studies have discovered advanced 3D printing techniques for fabricating 3D porous electrodes with improved performance.…”

MXene/Carbon Nanotube Hybrids: Synthesis, Structures, Properties, and Applications

“…Synthesis of MXene/CNT hybrids by thermal treatment generally involves an annealing step of the mixture of MXenes, metal catalysts (or the corresponding precursors) and the solid carbon sources under a protective atmosphere, as illustrated in Figure 3c. [84] As an example, Ti 3 C 2 T x /poly(methyl methacrylate) (PMMA) composites were initially prepared by self-assembly. [85] Then, ZIF-8 and ZIF-67 crystals were synthesized on the surface of Ti 3 C 2 T x after the successive deposition of Zn 2 + , Co 2 + , and organic ligands based on electrostatic interaction.…”