2D Ti₃C₂ MXene/WO₃ Hybrid Architectures for High‐Rate Supercapacitors

Abstract

Energy storage capabilities of transition metal oxides (TMOs) have expanded beyond the realm of ruthenium and manganese oxides to a versatile TMO like tungsten trioxide (WO3). The phase‐determined nature, such as intrinsic formation of hollow tunnels in the hexagonal polymorph of WO3 (Hexa WO3) and highly crystalline features in the monoclinic phase (Mono WO3), makes WO3 an attractive candidate for energy storage applications like supercapacitors. The development of superior WO3 supercapacitor electrode demands developing synergetic architectures with a variety of 2D materials like graphene, titanium carbide (Ti3C2) MXenes, etc. that can complement conductivity and stability. Here, the hybrids of Mono WO3–Ti3C2 and Hexa WO3–Ti3C2 are synthesized hydrothermally in one step by meticulously controlling the phase of WO3. The comparison of electrochemical performance reveals that the electrodes of 2D synergetic hybrid architectures almost double the specific capacitance (Csp) with respect to Mono WO3‐ and Hexa WO3‐only electrodes, exhibiting the highest Csp (566 F g−1) for Hexa WO3–Ti3C2, while retaining excellent life cycle (≈92%) of the initial Csp after 5000 cycles.

Surface Modification of a MXene by an Aminosilane Coupling Agent

“…For example, the functionalized MXenes can act as curing agents for epoxy resins and allow the development of electrically conductive composites . In addition, they can play the role of substrates for surface‐initiated atom transfer radical polymerization, electrodes for energy‐storage devices and metal ion absorber . The results presented in this article point to the potential of MXenes for self‐assembly, which permits bottom‐up manufacturing of nanodevices.…”

Two‐Dimensional Transition Metal Carbides and Nitrides (MXenes): Synthesis, Properties, and Electrochemical Energy Storage Applications

“…Recently, Guo et al partially removed gallery Al layers in Ti 3 AlC 2 to obtain Ti 3 C 2 T x with appropriate Al interlayers (Ti 3 C 2 T x @Al), which demonstrated excellent areal capacitances. In another report, hexagonal WO 3 was deposited on Ti 3 C 2 to enhance the electrical conductivity and surface area . Benefiting from the advanced architecture, the charge storage performance was greatly improved …”

“…In another report, hexagonal WO 3 was deposited on Ti 3 C 2 to enhance the electrical conductivity and surface area . Benefiting from the advanced architecture, the charge storage performance was greatly improved …”

“…We note that specifying the scan rate when reporting the capacitance is necessary, since the scan rate heavily affect the ion diffusion kinetics and thus the utilization of active sites. On the other hand, the specific capacitance of Ti 3 C 2 T x can be greatly improved by increasing the redox active sites such as nitrogen doping, enlarging the interlayer spacing, and/or mixing with pseudocapacitive materials (i.e., metal oxide) …”

One‐Pot Hydrothermal Synthesis of Ternary 1T‐MoS2/Hexa‐WO3/Graphene Composites for High‐Performance Supercapacitors

“…It has different crystalline phases, such as monoclinic WO 3 (mono‐WO 3 ) and hexagonal WO 3 (hexa‐WO 3 ). The hexa‐WO 3 possesses more rigid tunnels compared with mono‐WO 3 and allows fast ion/proton intercalation, leading to high charge storage capacity . However, low conductivity and poor cyclic stability of WO 3 were encountered during the application as electrode materials for supercapacitors.…”