PPy-PdO modified MXene for flexible binder-free electrodes for asymmetric supercapacitors: Insights from experimental and DFT investigations

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 487; p. 150555
• Main Authors: Vigneshwaran, J., Jose, Jemini, Thomas, Siby, Gagliardi, Alessio, Narayan, R.L., Jose, Sujin P.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-05-2024
• Subjects: Asymmetric supercapacitor; DFT; Electrodeposition; Quantum capacitance; V2C MXene; Electrodeposition; Asymmetric supercapacitor; V2C MXene; DFT; Quantum capacitance
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2024.150555

•Flexible, binder-free, and scalable electrodes of PPy-PdO modified MXenes.•The supercapacitor delivers remarkable energy density of 64.5 Wh kg−1at a power density of 980.9 W kg−1.•Experimental discoveries were substantiated through the DFT calculations.•Quantum capacitance of 2155 μF cm−2 at −0.48 V for V2C-PPy-PdO, which is the highest among the studied structures.•PdO in V2C-PPy enhances the electronic density of states improving conductivity and thus the energy storage capabilities.
Binder-free, flexible electrodes of V2C MXene, V2C-PPy, and V2C-PPy-PdO (a ternary composite of vanadium carbide, polypyrrole, and palladium oxide) were fabricated using a simplified, one-step electrodeposition method. A comprehensive assessment has subsequently been conducted on the microstructural and electrochemical attributes of these electrode materials when utilized in supercapacitors with a 1 M H2SO4 electrolyte. Notably, an impressive specific capacitance of 487F g−1 is achieved for V2C-PPy-PdO ternary composite at 1 A/g. This exceptional performance is due to the considerable active surface area and inherent structural stability of the host material. These factors significantly enhanced the electrochemical reaction kinetics and cyclic reversibility. Furthermore, the V2C-PPy-PdO composite demonstrated a notable specific capacitance of 250F g−1 when integrated into an asymmetric coin cell configuration alongside activated porous carbon under a current density of 1 A/g. Remarkably, it maintained an outstanding capacitance retention of 92 % across 10,000 charge–discharge cycles. Our experimental discoveries were additionally substantiated through the Density Functional Theory calculations, which unveiled that the inclusion of PdO within the V2C-PPy-PdO composite led to an augmentation of electronic states near the Fermi level. This increase in electronic states ultimately improved the quantum capacitance, rendering the V2C-PPy-PdO composite a highly promising candidate for supercapacitor applications.