Supercapacitor Performance of NiO, NiO-MWCNT, and NiO-Fe-MWCNT Composites

Aunggat Shah; Subhabrata Senapati; H C Ananda Murthy; Laishram Robindro Singh; Mrityunjoy Mahato

doi:10.1021/acsomega.3c03044

Supercapacitor Performance of NiO, NiO-MWCNT, and NiO-Fe-MWCNT Composites

ACS Omega. 2023 Sep 7;8(37):33380-33391. doi: 10.1021/acsomega.3c03044. eCollection 2023 Sep 19.

Authors

Aunggat Shah¹, Subhabrata Senapati¹, H C Ananda Murthy^{2

3}, Laishram Robindro Singh⁴, Mrityunjoy Mahato¹

Affiliations

¹ Physics Division, Department of Basic Sciences and Social Sciences, School of Technology, North-Eastern Hill University, Shillong, Meghalaya 793022, India.
² Department of Applied Chemistry, School of Applied Natural Science, Adama Science and Technology University, 1888 Adama, Ethiopia.
³ Department of Prosthodontics, Saveetha Dental College & Hospital, Saveetha Institute of Medical and Technical Science (SIMATS), Saveetha University, Chennai, Tamil Nadu 600077, India.
⁴ Department of Nanotechnology, School of Technology, North Eastern Hill University, Shillong, Meghalaya 793022, India.

Abstract

The NiO-CNT and NiO-Fe-CNT composites that have been prepared from waste high density polyethylene plastic and their carbon nanotube (CNT) quality-dependent supercapacitance tuning have been reported here. Multiwalled CNT (MWCNT) formation has been confirmed from TEM and Raman spectra with an I_D/I_G ratio of 0.77, which stands for high graphitization. The specific surface area (SSA) of MWCNTs in the NiO-Fe-CNT composite was 87.8 m²/g, while in the NiO-CNT composite, it was 25 m²/g. NiO-Fe-CNT displayed higher specific capacitance and energy density (1360 Fg^-1 and 1180 W h kg^-1) than NiO-CNT (1250 Fg^-1 and 1000 W h kg^-1), which may be due to the presence of higher-quality MWCNTs in the NiO-Fe-CNT composite. NiO-Fe-CNT displayed higher contributions of electric double-layer capacitor (59%) behavior compared to NiO-CNT (38%) and represented a hybrid supercapacitor. NiO-Fe-CNT also displayed a capacitive retention of 96% after 1000 charge-discharge cycles. Furthermore, studies in acidic electrolytes revealed higher performance of NiO-Fe-CNT than NiO-CNT, displaying specific capacitances of NiO-Fe-CNT to be 1147 Fg^-1 in 2 M H₂SO₄ and 943 Fg^-1 in 2 M HCl. It has been qualitatively explored that the quality of CNTs, SSA, and quantum confinement effects in the composites may be the factors responsible for the performance difference in NiO-Fe-CNT and NiO-CNT. The present work is geared toward the low-cost fabrication of high-quality CNT composites for supercapacitors and energy storage applications. The present work also contributes quantitatively to the understanding of CNT quality as an important parameter for the performance of CNT-composite-based supercapacitors.