MXene and MoS_{3- x} Coated 3D-Printed Hybrid Electrode for Solid-State Asymmetric Supercapacitor

Recently, 2D nanomaterials such as transition metal carbides or nitrides (MXenes) and transition metal dichalcogenides (TMDs) have attracted ample attention in the field of energy storage devices specifically in supercapacitors (SCs) because of their high metallic conductivity, wide interlayer spacing, large surface area, and 2D layered structures. However, the low potential window (ΔV ≈ 0.6 V) of MXene e.g., Ti₃ C₂ T_x limits the energy density of the SCs. Herein, asymmetric supercapacitors (ASCs) are fabricated by assembling the exfoliated Ti₃ C₂ T_x (Ex-Ti₃ C₂ T_x ) as the negative electrode and transition metal chalcogenide (MoS_{3- x} ) coated 3D-printed nanocarbon framework (MoS_{3- x} @3DnCF) as the positive electrode utilizing polyvinyl alcohol (PVA)/H₂ SO₄ gel electrolyte, which provides a wide ΔV of 1.6 V. The Ex-Ti₃ C₂ T_x possesses wrinkled sheets which prevent the restacking of Ti₃ C₂ T_x 2D layers. The MoS_{3- x} @3DnCF holds a porous structure and offers diffusion-controlled intercalated pseudocapacitance that enhances the overall capacitance. The 3D printing allows a facile fabrication of customized shaped MoS_{3- x} @3DnCF electrodes. Employing the advantages of the 3D-printing facilities, two different ASCs, such as sandwich- and interdigitated-configurations are fabricated. The customized ASCs provide excellent capacitive performance. Such ASCs combining the MXene and electroactive 3D-printed nanocarbon framework can be used as potential energy storage devices in modern electronics.