Enhanced performance of supercapacitor based on boric acid doped PVA-H 2 SO 4 gel polymer electrolyte system B. Karaman a , A. Bozkurt b,* a Department of Bio&Nano Technology Engineering, Istanbul University, Avcılar, _ Istanbul, Turkey b Department of Biophysics, Institute for Research and Medical Consultations(IRMC), Imam Abdulrahman Bin Faisal University, PO Box:1982 Dammam, 31441 Saudi Arabia article info Article history: Received 13 June 2017 Received in revised form 29 January 2018 Accepted 5 February 2018 Available online xxx Keywords: Ultracapacitor Gel polymer electrolyte Electrical double layer capacitor Proton conducting Energy density Power density abstract Proton Conducting gel polymer electrolytes (GPEs) are taking much attention compared to liquid electrolytes for supercapacitor applications because of their physical properties, electrochemical stability and operation over broader temperature window. Among different GPEs PVA/acid blend electrolytes such as PVA/H 2 SO 4 , has drawn great attention in recent years. In this study, PVA-H 2 SO 4 -H 3 BO 3 GPE was introduced for electric-double layer capacitor (EDLCs) application, in which electrospun free-standing carbon nanofibers are used as electrodes. Introduced PVA-H 2 SO 4 -H 3 BO 3 GPE serves as both separator and the electrolyte in the supercapacitor. Symmetric Swagelok cells including GPEs were assem- bled via using two electrode arrangements and the electrochemical properties were searched. Electrochemical performance studies demonstrated that PVA-H 2 SO 4 -H 3 BO 3 GPE had a maximum specific capacitance (Cs) of 134 F g 1 and showed great capacitance retention (%100) after 1000 charge/discharge cycles. Furthermore, PVA-H 2 SO 4 -H 3 BO 3 GPE yielded an energy density of 67 Wh kg 1 with a corresponding power density of 1000 W kg 1 at a current density of 1 A g 1 . © 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. Introduction Electrochemical capacitors (EC) are also referred as ultra- capacitors, are very popular in the electric vehicles, portable system industry and safe energy storage systems due to their high power supply in short term [1,2]. Electrochemical ca- pacitors are similar to batteries in design and store charges depending on both of these systems i.e. (i) pseudo capaci- tance, which includes active electrode material (ii) electric- double layer capacitor (EDLC) which bears electrochemically inactive material so that there is no a net ion exchange be- tween electrode and electrolyte. This is how energy stored in this system [3e5]. Although EDLCs have limited energy density, compared to the batteries, they have many advantages like high power density, good cycling stability, and safety which are mostly determined by the electrolytes that is used in EDLCs [4e7]. Consequently, increasing the energy density of these kind of capacitors is in a center of interest in these days [8]. Recently, gel polymer electrolytes have attracted a great attention as an alternative to liquid electrolytes for * Corresponding author. E-mail address: abozkurt@uod.edu.sa (A. Bozkurt). Available online at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/he international journal of hydrogen energy xxx (2018) 1 e9 https://doi.org/10.1016/j.ijhydene.2018.02.032 0360-3199/© 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. Please cite this article in press as: Karaman B, Bozkurt A, Enhanced performance of supercapacitor based on boric acid doped PVA- H 2 SO 4 gel polymer electrolyte system, International Journal of Hydrogen Energy (2018), https://doi.org/10.1016/j.ijhydene.2018.02.032