MnO2 nanosheets synthesized on nitrogen-doped vertically aligned carbon nanotubes as a supercapacitor electrode material

In the present study, nitrogen-doped vertically aligned carbon nanotubes (N-VACNTs) were synthesized on carbon cloth (CC) using the floating catalyst chemical vapor deposition (FCCVD) method, and MnO2 na-nosheets were grown on them using the hydrothermal method to produce an N-VACNT@MnO2 nano -composite structure. In this structure, a synergistic effect was obtained by combining N-VACNTs, which allow high electrical conductivity and fast ion transfer. In the galvanostatic charge-discharge (GCD) mea-surements performed separately in a three-electrode test cell using 1 M of Na2SO4 electrolyte, the specific capacitance of the N-VACNTs was found to be 53.7 F g-1 at a current density of 0.5 A g-1, and the specific capacitance of the N-VACNT@MnO2 electrode structure was found to be 497 F g-1. In addition, after 10,000 charge-discharge cycles at a current density of 10 A g-1, the N-VACNT electrode retained 99 % of its initial specific capacitance, while the N-VACNT@MnO2 electrode exhibited outstanding cyclic stability with 76 % of its initial specific capacitance. Moreover, in the as-fabricated asymmetric supercapacitor (ASC) using N-VACNTs and N-VACNTs@MnO2, the negative and positive electrodes achieved a stable voltage window of 0-1.7 V, with a specific capacitance of 59.4 F g-1 at a current density of 1 A g-1. Additionally, this ASC showed good cycling stability retaining 84 % of its specific capacitance at the end of 10,000 cycles. Therefore, this ASC structure with an energy density of 24.7 Wh kg-1 and a power density of 15.7 kW kg-1 are promising electrode materials for energy storage. (c) 2022 Elsevier B.V. All rights reserved.

Journal

JOURNAL OF ALLOYS AND COMPOUNDS

Year

2022

Volume

925

ISSN

0925-8388

eISSN

1873-4669

DOI

10.1016/j.jallcom.2022.166570

WoS UID

WOS:000897528200002