Composite Based on Multi-Walled Carbon Nanotubes and Manganese Oxide with Rhenium Additive for Supercapacitors: Structural and Electrochemical Studies

Abstract

The structure and electrochemical characteristics of composites based on multi-walled carbon nanotubes (MWCNTs) and manganese oxide with the addition of rhenium oxide has been studied. It has shown that the decorating of the MWCNT surface with layers or nanoparticles of manganese oxide (Mn(III) + Mn(IV)) provides more than a twofold increase in the value of the specific capacitance at low potential scan rates. However, composites based only on manganese oxide exhibit poor electrochemical behavior and the value of the specific capacitance decreases rapidly with increasing potential scan rate due to the limitation of diffusion processes. The addition of rhenium oxide to composites significantly increases their electrochemical properties due to changes in the chemical composition and morphology of composites. Studies of the structure and chemical state have shown that an improvement in the specific capacitance is provided by increasing in the proportion of Mn(IV) oxide in such composites, which has the ability to rapidly and completely reverse redox reactions and has lower electrical resistance values, compared to Mn(III) oxide. A detailed analysis of the voltammetric data showed that an increase in the rate capability in composites with the addition of rhenium oxide can also be provided by increasing the availability of the electrode surface for electrolyte ions and increasing the amount of charge stored due to the formation of a double electric layer.

Mechanically homogenized expanded graphite/ cobalt(II) rhenate(VII) – Co(ReO4)2, as electrodes in hybrid symmetric supercapacitors

“…Combination of active carbon with ammonium perrhenate allowed to produce an electrode material with an enhanced specific capacitance around 60F/g [7]. Similar results were obtained by reacting multiwalled carbon nanotubes with potassium permanganate and ammonium perrhenate [8]. ReS2 was also examined as a potential pseudocapacitive material, presenting high Coulombic efficiency and dramatic increase for initial hundreds of cycles [9].…”

Effect of Nanoparticle and Carbon Nanotube Additives on Thermal Stability of Hydrocarbon-Based Drilling Fluids

“…On the evidence from atomic force microscopy data, the length of the SWCNTs exceeded 4 μm, and their average and bulk densities were 1.8 and 0.1 g/cm 3 . Moreover, to improve the thermal stability of the drilling fluid, the effect of MWCNT additives, namely, Taunit-MD, produced by Nanotech Center (Tambov, Russia), was investigated [22]. The inner diameter of these MWCNTs was 5-15 nm, and the outer diameter was 8-30 nm.…”

Surface Engineering of Multi-Walled Carbon Nanotubes via Ion-Beam Doping: Pyridinic and Pyrrolic Nitrogen Defect Formation

“…Specifically, CNTs promise to emerge as fundamental components for advanced high-strength composites [5,6], sensitive components in gas sensors [7], and key elements in lithium-ion batteries [8]. At the same time, the need for effective materials to facilitate the cathodic oxygen reduction reaction (ORR), cold electron emitters, and chemical capacitor electrodes has increased the demand for nitrogen-doped carbon nanotubes (N-CNTs) [9][10][11][12][13]. This requirement is supported by the incorporation of nitrogen in various chemical configurations, intricately integrated into the graphene walls of the nanotubes.…”

“…Sci. 2023, 13, x FOR PEER REVIEW 2 of 14 carbon nanotubes (N-CNTs) [9][10][11][12][13]. This requirement is supported by the incorporation of nitrogen in various chemical configurations, intricately integrated into the graphene walls of the nanotubes.…”