Recently, the MXene itself and its composites with various metal oxides have shown excellent electrochemical performance due to the presence of multiple oxidation states. However, the restacking of MXene layers and poor electrical conductivity of metal oxides are major bottlenecks in their effective electrochemical transport, when they are applied individually. Herein, we report a novel manganese oxide/MXene (MnO 2 /MXene) composite material to overcome these critical issues. Sub-50 nm-thick MnO 2 nanowires (NWRs) were introduced inside the MXene to effectively stop the restacking as well as to increase the surface area of the supercapacitor (SC) electrode material. The special control on the thickness of NWRs is not only providing an opportunity to adjust them inside the MXene layers but also giving a high surface area. Electrochemical studies suggested that the MnO 2 /MXene composite behaves as an excellent electrode material for hybrid SCs, as compared to individual MXene and MnO 2 . Maximum specific capacitance (C sp ) of MXene, MnO 2 NWRs, and MnO 2 /MXene composite was observed to be about 527.8, 337.5, and 611.5 F/g, respectively. The calculated specific capacity of the MnO 2 /MXene composite was about 489.5 C/g at 1 A/g, which shows better performance as an electrode material for energy storage devices. The synthesized electrode material demonstrated excellent capacitance retention of about 96% up to 1000 cycles.
Recently, a new class of two-dimensional
(2D) materials, called
MXene, consisting of layers of transition-metal carbides and nitrides/carbonitrides
has been introduced. MXene, a multifunctional material with hydrophilic
nature and excellent electrical conductivity and chemical stabilities,
can be applied in diverse research areas such as energy harvesting
and its storage, water purification, thermal dissipation, and gas
sensing. To achieve the best quality of MXene, optimization of some
important synthetic parameters is highly required such as an optimized
etchant concentration to remove an “A” element from
the MAX phase and sonication time for the efficient exfoliation of
MXene flakes. Besides, there is a need to disclose that particular
solvent through which intercalation can easily be achieved. In this
work, we optimized the abovementioned critical parameters for the
synthesis of good-quality MXene. Our results clearly explain the variations
in the quality of MXene under applied etchant concentrations, solvents
for better intercalation, and optimization of sonication time for
better exfoliation. The obtained results suggest that 30% HF as an
etchant, dimethyl sulfoxide (DMSO) as a solvent, and 135 min as the
sonication time are effective parameters for the synthesis of good-quality
MXene. We expect that this report will be helpful for the young research
community to synthesize good-quality MXene with the required properties.
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