Pseudocapacitive Charge Storage in MXene–V₂O₅ for Asymmetric Flexible Energy Storage Devices

Abstract

Pseudocapacitive asymmetric supercapacitors are promising candidates for achieving high energy density in flexible energy storage devices. However, seeking suitable positive electrode materials that are compatible with negative electrode materials remains a considerable challenge. In the current study, a pseudocapacitive Ti 3 C 2 T x MXene used as negative electrodes is rationally compatible with redox-type V 2 O 5 as positive electrodes, resulting in the assembly of an all-pseudocapacitive Ti 3 C 2 T x MXene//V 2 O 5 asymmetric flexible energy storage device. The solid-state asymmetric device can deliver an energy density of 8.33 mW h cm −3 at a current density of 0.5 A g −1 . Moreover, it can operate in an expanded voltage window of 1.5 V, with dominant surface-capacitive charge-storage mechanisms. Additionally, the device can power a yellow light-emitting diode for up to 7 s, indicating the potential of the device for use in practical applications. This study demonstrates the possibility of using other two-dimensional transition-metal carbide nanosheets for high-energy density flexible energy storage devices.

1T-VS2/MXene Hybrid as a Superior Electrode Material for Asymmetric Supercapacitors: Experimental and Theoretical Investigations

“…Figure a shows the schematic of the synthesis procedure of pristine VS 2 , and Figure b displays the preparation of VS 2 /MXene composites of VS 2 by adding different concentrations of MXene named VS 2 -MX-20, VS 2 -MX-50, and VS 2 -MX-80 by an in situ hydrothermal method. The as-prepared samples were characterized by p-XRD to identify the crystal structure Figure a illustrates the p-XRD patterns, where the characteristic peak of Ti 3 C 2 T x (MXene) at 2θ = 8.82° corresponding to the (002) plane . The shift of the characteristic peak to lower angle demonstrates the successful etching of the Al layer from Ti 3 AlC 2 (MAX).…”

“…2a illustrates the p-XRD patterns, where the characteristic peak of Ti 3 C 2 T x (MXene) at 2θ = 8.82°corresponding to the (002) plane. 33 The shift of the characteristic peak to lower angle demonstrates the successful etching of the Al layer from Ti 3 AlC 2 (MAX). The XRD profile of 1T-VS 2 in Figure 2a shows the hexagonal structure with a space group of P3m1.…”

Design and characterization of 2D MXene-based electrode with high-rate capability

“…As such, FTIR can be for instance used to detect the presence of surface groups or to assess the quality and purity of the synthesized compounds. 84 Similar to FTIR, Raman spectroscopy uses the interaction of photons (typically laser light) with molecular vibrations, phonons, or other excitations in the system. These interactions may slightly in or decrease the photon's energy, named Raman scattering.…”

Covalent‐Induced Heterostructure of Covalent‐Organic Frameworks and MXene as Advanced Electrodes with Motivated Pseudocapacitance Performance

“…Mostly, pseudocapacitive electrode materials could deliver higher capacitance and energy density than electrode materials with double‐layer capacitance character [11,12] . Although various pseudocapacitive electrode materials have been widely reported, including metal oxides, metal hydroxides and conductive polymers [13–15] . Unfortunately, these materials inevitably suffer from the inferior electrical conductivity, depressed kinetics and barren redox active sites, leading to their unsatisfactory rate capability, power density and cyclic stability [16] .…”