Iron Sulfide Microspheres Supported on Cellulose-Carbon Nanotube Conductive Flexible Film as an Electrode Material for Aqueous-Based Symmetric Supercapacitors with High Voltage

Jincy Parayangattil Jyothibasu; You-Ching Tien; Zi-Ting Chen; Hongta Yang; Tzu Hsuan Chiang; Ahmed F M El-Mahdy; Rong-Ho Lee

doi:10.1021/acsomega.4c03232

Iron Sulfide Microspheres Supported on Cellulose-Carbon Nanotube Conductive Flexible Film as an Electrode Material for Aqueous-Based Symmetric Supercapacitors with High Voltage

ACS Omega. 2024 Jun 6;9(24):26582-26595. doi: 10.1021/acsomega.4c03232. eCollection 2024 Jun 18.

Authors

Jincy Parayangattil Jyothibasu¹, You-Ching Tien¹, Zi-Ting Chen¹, Hongta Yang¹, Tzu Hsuan Chiang², Ahmed F M El-Mahdy³, Rong-Ho Lee^{1

4}

Affiliations

¹ Department of Chemical Engineering, National Chung Hsing University, Taichung 402, Taiwan.
² Department of Energy Engineering, National United University, Miaoli 360302, Taiwan.
³ Department of Materials and Optoelectronic Science, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan.
⁴ Department of Chemical Engineering and Materials Science, Yuan Ze University, Taoyuan 320, Taiwan.

Abstract

Nanostructured iron disulfide (FeS₂) was uniformly deposited on regenerated cellulose (RC) and oxidized carbon nanotube (CNT)-based composite films using a simple chemical bath deposition method to form RC/CNT/FeS₂ composite films. The RC/CNT composite film served as an ideal substrate for the homogeneous deposition of FeS₂ microspheres due to its unique porous architecture, large specific surface area, and high conductivity. Polypyrrole (PPy), a conductive polymer, was coated on the RC/CNT/FeS₂ composite to improve its conductivity and cycling stability. Due to the synergistic effect of FeS₂ with high redox activity and PPy with high stability and conductivity, the RC/CNT/FeS₂/PPy composite electrode exhibited excellent electrochemical performance. The RC/CNT/0.3FeS₂/PPy-60 composite electrode tested with Na₂SO₄ aqueous electrolyte could achieve an excellent areal capacitance of 6543.8 mF cm^-2 at a current density of 1 mA cm^-2. The electrode retained 91.1% of its original capacitance after 10,000 charge/discharge cycles. Scanning electron microscopy (SEM) images showed that the ion transfer channels with a pore diameter of 5-30 μm were formed in the RC/CNT/0.3FeS₂/PPy-60 film after a 10,000 cycle test. A symmetrical supercapacitor device composed of two identical pieces of RC/CNT/0.3FeS₂/PPy-60 composite electrodes provided a high areal capacitance of 1280 mF cm^-2, a maximum energy density of 329 μWh cm^-2, a maximum power density of 24.9 mW cm^-2, and 86.2% of capacitance retention after 10,000 cycles at 40 mA cm^-2 when tested at a wide voltage window of 1.4 V. These results demonstrate the greatest potential of RC/CNT/FeS₂/PPy composite electrodes for the fabrication of high-performance symmetric supercapacitors with high operating voltages.