An efficient strategy for transferring carbon nanowalls film to flexible substrate for supercapacitor application

The success to transfer graphene films and its engineering architecture, such as carbon nanowalls (CNWs), from the growth substrate to target substrate with large surface area and minimum structural damage is crucial for the future of graphene-based devices. Herein, we purpose a facile and an efficient strategy for transferring CNWs film grown on SiO₂/Si substrate to flexible Indium Tin Oxide-Polyethylene Naphthalate (ITO-PEN) substrate. The feasibility of the proposed transfer method is demonstrated by studying the morpho-structural features of the transferred carbon nanowalls (TCNWs) vs the as-grown CNWs using FE-SEM, TEM, EDX, and Raman spectroscopy characterisation techniques. The transfer method successfully provides non-wrinkle and crack-free TCNWs film that preserve mostly the features of as grown CNWs. The TCNWs films with and without anodically deposited Manganese Oxide (MnO₂) nanoparticles are explored as possible electrodes for energy storage applications. The MnO₂/TCNWs hybrid film ensures a high areal capacitance of 40.3 mFcm⁻² and preserves 75% of its initial capacitance as the charging current density increased from 1.0 to 6.0 mA cm⁻² and capacitance retention of 99.5% after 2000 cycles at 1.0 mA cm⁻². The contribution of this paper resides in paving the way for creating new opportunities for flexible energy storage devices.