The energy density of supercapacitors with carbon-based electrode materials is generally restricted by their limited electric double-layer capacitance (EDLC). The introduction of electroactive molecules to acquire abundant pseudocapacitance represents an efficient way to achieve a high-performance capacitor system. Herein, this work anchors redox-active tetramino-benzoquinone (TABQ) with multiwalled carbon nanotubes (MWCNTs) to form a composite (denoted as TABQ-MWCNTs). Due to the strong π–π stacking and H-bonding interaction between TABQ molecules and the MWCNT host, the TABQ-MWCNTs acquire enhanced structural stability and shortened pathway for electrons/charges, which facilitate their energy storage capability. Specifically, by adjusting the mass ratio of TABQ to MWCNTs, the composite can attain a high specific capacitance of 463 F g–1 at 1 A g–1 compared to that of bare MWCNTs (17 F g–1). Theoretical calculations show that TABQ-MWCNTs own a lower adsorption energy toward H+, suggesting its better EDLC capability through charge accumulation. Moreover, in situ Fourier transform infrared spectroscopy (FTIR) and Raman tests reveal that the TABQ molecules hosted on MWCNTs undergo a reversible evolution of the quinone-to-phenol structure during the discharging/charging process, further verifying its promising pseudocapacitance through faradic reactions. In addition to the high capacitance, the TABQ-MWCNT composite also exhibits good cyclability in a three-electrode system, i.e., 76.8% of the initial capacitance is obtained after cycling for 6000 times at 10 A g–1. An asymmetric supercapacitor (ASC) of TABQ-MWCNTs//activated carbon achieves a high energy density of 15.6 Wh kg–1 at a power density of 700 W kg–1. Moreover, it also shows a long-term cyclability of 91.5% after 10,000 cycles at 5 A g–1.
Transition metal-based compounds with high theoretical capacitance and low cost represent one class of promising electrode materials for high-performance supercapacitors. However, their low intrinsic electrical conductivity impedes their capacitive effect and further limits their practical application. Rational regulation of their composition and structure is, therefore, necessary to achieve a high electrode performance. Herein, a well-designed carbon-encased mixed-metal selenide rooted with carbon nanotubes (Ni-Co-Se@C-CNT) was derived from nickel–cobalt bimetallic organic frameworks. Due to the unique porous structure, the synergistic effect of bimetal selenides and the in situ growth of carbon nanotubes, the composite exhibits good electrical conductivity, high structural stability and abundant redox active sites. Benefitting from these merits, the Ni-Co-Se@C-CNT exhibited a high specific capacity of 554.1 C g−1 (1108.2 F g−1) at 1 A g−1 and a superior cycling performance, i.e., 96.4% of the initial capacity was retained after 5000 cycles at 10 A g−1. Furthermore, a hybrid supercapacitor assembled with Ni-Co-Se@C-CNT cathode and activated carbon (AC) anode shows a superior energy density of 38.2 Wh kg−1 at 1602.1 W kg−1.
There is great concern on the electromagnetic compatibility problem of electronic equipments in an intelligent substation, due to the compact structure resulted from high degree of integration between the primary electrical equipments and secondary electronic equipments. The very fast transient electromagnetic disturbance (VFTED) resulted from the gas insulated substation (GIS) switching operation has potential impact on the electronic equipments by the electromagnetic coupling between the VFTED and the circuit of “sensor-cable-intelligent electronic device (IED)”. This paper presents both experimental and theoretical results of the disturbance voltage induced on the ports in control cabinets during the disconnectors operating in a 500kV GIS substation. The considered ports are connected to a current transformer (CT) equipped nearby GIS switcher via a KVVP cable. The results show that the peak value, the duration time and the frequency range of the transient waveform are about 400V, 2 μs, and below 40 MHz.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2025 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.