Date of Award
Spring 5-13-2023
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Chemistry
First Advisor
Dr. Ram K. Gupta, rgupta@pittstate.edu
Second Advisor
Dr. Khamis Siam, ksiam@pittstate.edu
Third Advisor
Dr. Anuradha Ghosh, aghosh@pittstate.edu
Keywords
Energy storage devices, Supercapacitors, Polyaniline, Carbonized polyaniline, Activated carbon, Heteroatom dropped polyaniline
Abstract
With the increase in global population, the demand for the energy required for daily activities including household necessities, electronic and electric devices, etc. enhances at an alarming proportion. Under these circumstances, supercapacitors (SCs) have attracted great attention as electrochemical energy storage devices. Nowadays, most commercially available supercapacitors are composed of metallic compounds. Due to the high consumption, and limited availability of these elements, it is necessary to find an alternative, effective, low-cost materials in place of using it. With the purpose of achieving high electrochemical performance, this research work focuses on developing carbon derived from polyaniline (PANI) as an efficient electrode material for SCs. Here, chemical oxidative polymerization was used for the synthesis of PANI. Subsequently, the nitrogen-doped porous activated carbon (PAC) was produced through the chemical activation process of PANI nanotubes with potassium hydroxide (KOH). Herein, three different samples of PAC were synthesized by controlling the mass ratio of polyaniline to KOH ratios 1:0.5, 1:1, and 1:2. The changes in surface area and porosity were examined via BET analysis. It was observed that the surface area and pore volume from as-synthesized PANI to chemically treated samples were significantly improved from 18 to 3525 m2/g.The electrochemical performance of all materials was tested using both a three-electrode cell system and a symmetrical coin-cell supercapacitor (SCCS). Electrodes made from PANI to KOH, 1:1 wt. ratio showed better electrochemical performances in an aqueous electrolyte (KOH) in both systems. This material exhibited the highest capacitance of 378 F/g (at 0.5 A/g) and 143 F/g (at 0.5 A/g) in the three-electrode system and SCCS, respectively. The SCCS achieved a maximum energy density of 23 Wh/kg and a power density of 12 kW/kg. Further, this material has a higher stability, showing a good coulombic efficiency of about 99% with capacitance retention of 97% at 7 A/g after 10000 charge-discharge cycles. Like electrode material, the type of electrolyte also acts as the decisive factor in fabricating supercapacitors. By using aqueous, organic, and ionic liquid (IL) electrolytes, the electrochemical performance of the best sample (PANI: KOH= 1:1) was studied by fabricating coin cell supercapacitors. This sample was further analyzed through the heteroatom doping process. Herein, the N, P, S, and B-doped PANI samples were obtained by treating them with HNO3, H3PO4, H2SO4, and H3BO3 acids, respectively. B-doped PANI showed the highest specific capacitance of 269 F/g (0.5 A/g) and 97 F/g (0.5 A/g) in the three-electrode system and SCCD in aqueous electrolyte (KOH), respectively. Moreover, this SCCS achieved a maximum energy density of 14 Wh/kg with a power density of 3441 W/kg using B-doped PANI-based electrodes.
This research suggests that activated carbon derived from PANI material showed higher electrochemical performance in aqueous KOH electrolyte for supercapacitors which could be adopted for commercial applications. Considering the performance of the aqueous, organic, and IL electrolytes, SCs made with IL showed a higher energy density with a high-power density without disturbing the specific capacitance.
Recommended Citation
Kangane Arachchige, Udeshika, "SYNTHESIS AND CHARACTERIZATION OF POLYANILINE-BASED HIGH-PERFORMANCE CARBON FOR ENERGY STORAGE APPLICATIONS" (2023). Electronic Theses & Dissertations. 641.
https://digitalcommons.pittstate.edu/etd/641
