Synthesis and electrochemical performance of an electroactive nitrogen-doping SnO₂ nanoarray supported on carbon fiber

Abstract

An electroactive nitrogen-doping tin dioxide nanorod array (N-SnO2 NRA) is designed as an effective energy-storage electrode material for supercapacitor applications. N-SnO2 supported on a carbon fiber substrate is prepared using SnCl4 as a precursor through hydrolysis, hydrothermal growth, and an NH3-nitriding process. Electroactive N-SnO2 is formed by an N-doping reaction between Sn(OH)4 and NH3, revealing a high nitrogen-doping level of 12.5% in N-SnO2. N-SnO2/carbon fiber reveals a lower ohmic resistance and charge transfer resistance than SnO2/carbon fiber, which is consistent with its higher current response and lower voltage drop in electrochemical measurements. N-SnO2 NRA has an independent nanoarray structure and a small side length of a quadrangular nanorod, contributing to a more accessible interspace, reactive sites, and feasible electrolyte ion diffusion. The N-SnO2/carbon fiber NRA electrode shows higher specific capacitance (105.4 F g−1 at 0.5 A g−1) and rate capacitance retention (45.0% from 0.5 to 5 A g−1) than a SnO2/carbon fiber NRA electrode (58.6 F g−1, 38.4%). Significantly, the cycling capacitance retention after 2000 cycles increases from 78.1% of SnO2/carbon fiber to 98.8% of N-SnO2/carbon fiber, presenting a superior electrochemical cycling stability. The N-SnO2 supercapacitor maintains stable power working at an output voltage of 1.6 V. The specific capacitance decreases from 75.2 to 55.1 F g−1 when the current density increases from 1 to 10 A g−1. The corresponding energy density decreases from 24.23 to 9.81 Wh kg−1, presenting a reasonable rate capability. So, the prepared N-SnO2 nanorod array demonstrates superior capacitance performance for energy-storage applications.

Dual Applications of Cobalt-Oxide-Grafted Carbon Quantum Dot Nanocomposite for Two Electrode Asymmetric Supercapacitors and Photocatalytic Behavior

“…The Co 3 O 4 , CQD, and Co 3 O 4 –CQD impedance spectra involve an electrochemical fitting process, as exhibited in Figure a–c. The fitting process gives the equivalent circuits containing solution resistance ( R s ), charge transfer resistance ( R ct ), Warburg impedance element ( W ), and constant phase element (CPE). , A Nyquist plot has two distinct parts which include a semicircle in the higher-frequency region and a sloped straight line in the higher-frequency region . The R s values of the prepared materials are Co 3 O 4 (2.83 Ω), CQD (1.68 Ω), and Co 3 O 4 –CQD (1.54 Ω), and the R ct values are Co 3 O 4 (5.53 Ω), CQD (4.50 Ω), and Co 3 O 4 –CQD (4.20 Ω).…”

“…The fitting process gives the equivalent circuits containing solution resistance ( R s ), charge transfer resistance ( R ct ), Warburg impedance element ( W ), and constant phase element (CPE). 83 , 84 A Nyquist plot has two distinct parts which include a semicircle in the higher-frequency region and a sloped straight line in the higher-frequency region. 85 The R s values of the prepared materials are Co 3 O 4 (2.83 Ω), CQD (1.68 Ω), and Co 3 O 4 –CQD (1.54 Ω), and the R ct values are Co 3 O 4 (5.53 Ω), CQD (4.50 Ω), and Co 3 O 4 –CQD (4.20 Ω).…”

Photoelectrochemical performance of tubewall‐separated titanium dioxide nanotube array photoelectrode

“…Photoelectrochemical active materials such as transition metal oxides/sulfates/nitrides, polyoxometalates, conductive polymers, and their composites have been widely investigated in the area of photochemical catalysis and electrochemical energy conversion or storage 1–6 . The photoelectrochemical performance of these active materials is highly related to their inherent properties and microstructures as well 7 .…”