Surface Modification of Sputtered Carbon Supercapacitor Electrode by Hydrogen Annealing MUHAMMAD Uzair Iqbal 1,a* , NOOR Zaman 1,b , MUHAMMAD Shahid 1,c , AZHAR Hussain 1,d and RAMZAN Karim 2,e 1 Department of Metallurgy and Material Engineering, UET, Taxila, Pakistan 2 Department of Metallurgy and Materials Engineering, GIKI, Topi, Swabi, Pakistan a uzairiqbal800@gmail.com, b noorzaman590@gmail.com, c engrmshahid05@gmail.com, d azharhussain@uettaxila.edu.pk, e ramzan.karim@giki.edu.pk Keywords: Supercapacitor Electrode, Graphene, Hydrogen Annealing, Carbon Sputtering. Abstract. In the applications of renewable energy; use of energy in the electric vehicles and many other electronic devices such as mobile devices and computers; electrical energy storage is essential. Batteries are used to store electrical energy but have low power density and lower cycle life. Using extremely porous electrode materials for supercapacitors, based on quick ion transport, are specialized to provide high power density, long stability and effective energy storage. Using graphene-based electrode is the best way to boost the energy density of supercapacitor. Graphene synthesized by chemical exfoliation, ultrasonic exfoliation and solution based chemical reduction suffers agglomerations that tends to restack the graphene sheets. In the present work, we studied the option of hydrogen gas annealing to obtain graphene from amorphous carbon film, coated on Cu substrate using sputtering. For electrochemical assessment, in situ developed film was compared with graphene applied from other methods of graphene synthesis. Atomic force microscopy (AFM) results revealed that annealed carbon sputtered electrode has high route mean square (RMS) roughness i.e., 181.5 nm, most probably because of graphene formation. Cyclic voltammogram (CV) results show less area curve for annealed electrode which depicts high active area for charge storage and enhanced conductivity due to deposited graphene layer. Introduction As energy demand continues to rise, researchers are looking for alternate energy sources such as wind and solar [1].However, if the energy acquired from those resources can be correctly stored, the highest advantage from these environment friendly resources can be accomplished. Capable energy storage systems are necessary to achieve this objective [2]. Rechargeable batteries are usually used for energy storage purposes. However, they experience numerous inconveniences in the context of large-scale storage, such as low power density, restricted lifetime, and fast capacity decrease. In the case of supercapacitors these drawbacks can be resolved [3]. Supercapacitors offers high power density, long cycle life, high charging discharging and exceptional cyclic stability making them promising candidate for large-scale energy storage applications. The supercapacitor’s performance depends upon the characteristics of electrode and electrode/electrolyte interfaces [3–5]. Supercapacitors are categorized into two kinds based on energy storage mechanism i.e., electrochemical double layer capacitors (EDLCs), pseudo capacitors [5]. The capacitance of EDLCs comes from the accumulation of charge at the interfaces of electrode- electrolyte. Therefore, controlling the specific surface area, pore size and increasing electrical conductivity are the efficient way to attain high storage ability [6]. The energy storage of pseudo- capacitance is achieved by moving faradic charges between electrode and electrolyte owing to reversible multi-electron redox faradic responses, which usually exhibit high specific capacitance and greater energy density than EDLCs [7].The bad electrical conductivity in the widely recognized pseudocapacitive electrodes, can limits the faradic responses, resulting in unsatisfactory electrochemical results and life cycles. However, activated carbon (AC), carbon nanotubes (CNTs) and graphene were investigated as electrode materials for electrolytic double layer capacitors (EDLCs) due to their excellent physical Key Engineering Materials Submitted: 2019-10-14 ISSN: 1662-9795, Vol. 875, pp 49-54 Revised: 2020-02-28 © 2021 Trans Tech Publications Ltd, Switzerland Accepted: 2020-06-23 Online: 2021-02-04 All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications Ltd, www.scientific.net. (#548521471, UET, Taxila, Pakistan-16/12/20,17:57:38)