Synthesis of Ultrathin MnO₂ Nanowire-Intercalated 2D-MXenes for High-Performance Hybrid Supercapacitors

Abstract

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.

Synthesis, Characterization, Photocatalysis, and Antibacterial Study of WO3, MXene and WO3/MXene Nanocomposite

“…Figure 6 shows the FTIR spectra of MXene, WO 3 and WO 3 /MXene nanocomposite. In the case of MXene, the absorption band present at around 3545 cm −1 was attributed to the absorbed water, which was due to the hydrophilic nature of MXene [60]. The bands present in the range of 2000-2500 cm -1 showed a methyl/methylene group (-CH 3 , CH…”

MXene-Derived Quantum Dots for Energy Conversion and Storage Applications

“…These are (1) the 2D lamellar morphology enables the fast ion transport and intercalation of different metals ions into the 2D sheet enhance the energy storage performance; (2) high electrical and metallic conductivity enhance the electron transport and increase the capacitive performance; (3) surface redox activity like other transition metal elements; (4) the surface functional group of Ti 3 C 2 T x ( x = −O, −OH, −F) increases the hydrophilicity and significantly impacts the charge-storage mechanism in aqueous electrolytes. Also, the surface functional group supplies abundant catalytic sites and affects the electrocatalytic performance; and (5) its high surface area increases the capacitive behavior. − Thus, MXene-based catalysts exhibit a higher electrocatalytic performance toward energy storage applications. − Further, to increase the energy storage performance, different engineering strategies have been adapted to enhance the capacitance value of MXene and decrease the particle size or synthesize the quantum dots on them. The smaller size lowers the ion diffusion path and makes easy electrolytes available to the catalytic sites, improving energy storage performance.…”

Review on MXene synthesis, properties, and recent research exploring electrode architecture for supercapacitor applications

“…131 Nanowires of MnO 2 are also a better composite to hybrid with MXenes for enhancing capacitance. 141 For getting excellent deformability and editability, Xie et al developed the idea of incorporating metalorganic frameworks with MXenes. This provides better electrochemical performance and flexibility.…”