Improvement of morphological structure and electrochemical charge storage performance of a new poly(terthiophene)-based conducting film through side-chain engineering


Yiğit D.

New Journal of Chemistry, vol.47, no.38, pp.18055-18069, 2023 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 47 Issue: 38
  • Publication Date: 2023
  • Doi Number: 10.1039/d3nj03557c
  • Journal Name: New Journal of Chemistry
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Biotechnology Research Abstracts, Chemical Abstracts Core, Chimica, Compendex, DIALNET
  • Page Numbers: pp.18055-18069
  • Lokman Hekim University Affiliated: Yes

Abstract

In this work, a new poly(2,2′:5′,2′′-terthiophene) derivative with an electron-rich pendant group was designed using a side-chain engineering approach to prepare high performance redox-active electrode materials for electrochemical energy storage applications. The poly(2-((2-(4-(([2,2′:5′,2′′-terthiophen]-3′-ylmethylene)amino)phenoxy)ethyl)thio)ethanol) (PKAAN) was electrodeposited via a constant potential electrolysis method on stainless steel current collector substrates without any template material or polymeric binder and directly used as a redox-active electrode material. The non-substituted poly(2,2′:5′,2′′-terthiophene) (PTTh) conducting polymer derivative was also prepared to assess the effect of the side chain substituent on the morphological, mechanical and charge storage performance of the PKAAN redox-active electrode material. The morphological features of the PKAAN- and PTTh-based conducting polymer films were monitored by scanning electron microscopy (SEM). Cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS) techniques were employed to examine the electrochemical performances of the redox-active electrodes in both 3-electrode and 2-electrode cell configurations. The SEM evaluations revealed that the PKAAN electroactive film possesses a unique 3D and porous morphology offering more effective diffusion pathways for ion transportation during the charge/discharge cycles compared to the PTTh polymeric network. The PKAAN redox-active electrode material achieved superior electrochemical charge storage performance with a gravimetric specific capacitance of 369 F g−1 at a constant current density of 2.5 mA cm−2 at a potential of 1.85 V in single electrode measurements. Furthermore, the PKAAN electrode exhibited outstanding cycling durability and mechanical stability upon long-term cycling. The PKAAN redox-active electrode material retained 93% of its initial capacitance at the end of 12 500 repeating charge/discharge cycles. The solid-state symmetrical supercapacitor device assembled using PKAAN electrodes delivered a specific capacitance of 205 F g−1, an energy density of 77.5 W h kg−1 and a power density of 750 W kg−1 in an operating voltage window of 1.85 V. In addition to its energy storage behavior, the supercapacitor device demonstrated excellent cycling stability with a capacitance decrease of only 7.5% after 12 500 repeated cycles. The results reveal that the side-chain engineering strategy can be used as a facile and effective way to design conducting polymer-based electrode materials with desired morphological, mechanical and electrochemical features for high-performance energy storage applications.