Electrochemical study of Ni-Intercalated Nb2C MXene and LASER Scribed polyimide electrodes for energy storage; an experimental and computational analysis Ayesha Zaheer

Abstract

Energy production and storage is a hot topic of pronounced importance in today's world of energy crisis, and therefore researchers across the globe have put their efforts to cultivate solutions in this realm. Since Nb2CTx MXene has been shown pronounced reputation as eminent electrode materials for supercapacitors so we have synthesized 2D Nb2CTx MXene and Ni-doped Nb2CTx by opting Substantial hydrothermal route. The doping was further confirmed by using X-ray diffraction (XRD), scanning electron microscopy (SEM), Transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDXS), Brunauer–Emmett–Teller (BET), Fourier transformed infra-red spectroscopy (FTIR) and Raman spectroscopy. The as prepared samples were deposited over glassy carbon electrode (GCE) and electrochemical properties were studied using cyclic voltammetry (CV). The introduction of Nickel into MXene sheets causes the surface area of Nb2CTx MXene to increase from 5.2149 m2g-1 to 18.0221 m2g-1 providing additional active sites which boost the current density as well as capacitance. Moreover, an embracive comparison of H2SO4 and PVA-H2SO4 was done. The maximum capacitance value of 8.5 mF/g was achieved with Ni-doped MXene in PVA-H2SO4. This depicts that PVA-H2SO4 electrolyte possessed excellent conductivity and sanctioned quicker and easier surface redox reactions which lead to pseudo-capacitance. Computational analysis were also studied using Density Functional Theory (DFT) utilizing Wein2k software and structure, Density of states (DOS), Band structure and Electron density of state (EDOS) was explained that are complimenting the experimental results. To our best knowledge, MXene film has never been reported so far in the fabrication of flexible micro supercapacitors electrodes so in this regard we have proposed the Cost –effective method of laser scribed reduced polyimide electrodes as well as reduced polyimide electrodes followed by Spin coating of MXene ink. Moreover, the electrochemical assets of both the set of electrodes were evaluated in a three-electrode system in 3-different electrolytes i.e. H2SO4, PVA-H2SO4, IL/PVA/H2SO4. Maximum Areal capacitance of 9.98 mF/cm2 was achieved with MXene - rPI hybrid. Thus MXene-rPI hybrid showed much better capacitive performance as compared to the pristine laser scribed polyimide sheet. This scheme provides a quick route to enhance the performance of carbon-based materials for flexible and wearable electronics.