Rotational chemical bath deposited flexible MnO<sub>2</sub>/MXene thin film as an electrode for all solid state asymmetric supercapacitor.

Abstract

MXenes are stealing the spotlight due to their metallic conductivity and hydrophilicity; however, the restacking of 2D layers in MXene hampers the electrochemical performance. On the contrary, MnO₂is considered a promising electrode material for its variable oxidation states, but its weak conductivity limits practical applications. Taking the complementary properties, studies on the<i>in-situ</i>synthesis of MnO₂@MXene by chemical bath deposition (CBD) for energy-related (supercapacitor) applications have not yet been explored. Thus, exploring the opportunity for the first time to examine the performance of MnO₂/Ti₃C₂T<i>_x</i>supercapacitor applications by directly growing nano architectures on a flexible stainless steel mesh substrate utilising a binder-free synthesis approach was of our interest. With this motivation, the present investigation deals with a MnO₂/Ti₃C₂T<i>_x</i>(MnO₂/MXene) composite thin film designated as an MMC electrode deposited on the stainless steel mesh (300 mesh size) via an<i>in-situ</i>modified CBD method called rotational CBD (R-CBD). The synthesised MMC exhibits an excellent specific capacitance of 1130 F g^-1when compared to MnO₂(628.3 F g^-1) and MXene (32.5 F g^-1) at a current density of 1 mA cm^-2. A flexible MnO₂/MXene//MXene-based asymmetric supercapacitor device exhibited specific capacitance of 43.7 F g^-1at 2 mA cm^-2current density, maximum energy density (6.06 Wh kg^-1), and power density (0.6 kW kg^-1).