Directly Grown Multiwall Carbon Nanotube and Hydrothermal MnO2 Composite for High-Performance Supercapacitor Electrodes

Abstract

MnO2–MWNT–Ni foam supercapacitor electrodes were developed based on directly grown multiwalled carbon nanotubes (MWNTs) and hydrothermal MnO2 nanostructures on Ni foam substrates. The electrodes demonstrated excellent electrochemical and battery properties. The charge transfer resistance dropped 88.8% compared with the electrode without MWNTs. A high specific capacitance of 1350.42 F·g−1 was reached at the current density of 6.5 A·g−1. The electrode exhibited a superior rate capability with 92.5% retention in 25,000 cycles. Direct MWNT growth benefits the supercapacitor application for low charge transfer resistance and strong MWNT–current collector binding.

N-Dopant-Mediated Growth of Metal Oxide Nanoparticles on Carbon Nanotubes

“…Interestingly, the MnO x nanoparticles directly synthesized on the N-doped graphitic surface have a spherical shape with a highly uniform diameter of less than 10 nm ( Figure 2 F). They are distinct from flake-like or rod-like MnO x nanoparticles, generally synthesized on pristine CNTs, as reported in many previous studies [ 28 , 29 , 30 ]. The conformal and uniform formation of MnO x nanoparticles on NCNTs can be elucidated with the even distribution of N dopants over the whole surface and the well-aligned separated structures of the grown NCNTs, which prevent non-uniform nucleation or hidden surfaces resulting from agglomeration.…”

Electrostatic flocking MnO 2 nanofiber electrode for long cycling stability supercapacitors

“…4.1 Ω) compared with dopping MnO 2 electrode (ca.12.6 Ω), indicating a lower interfacial resistance ( R ct ) of ion diffusion from electrolyte to MnO 2 . The result was atttributed to the direct exposure of MnO 2 to electrolyte for the electrostatic flocking MnO 2 electrode 28 …”

“…The result was atttributed to the direct exposure of MnO 2 to electrolyte for the electrostatic flocking MnO 2 electrode. 28 Figure 6 shows the electrochemical performance of SSCs based on electrostatic flocking MnO 2 electrode. The CV curves were rectangular shapes, indicating typical capacitive behavior.…”

Spinel LiMn2O4 nanoparticles fabricated by the flexible soft template/Pichini method as cathode materials for aqueous lithium-ion capacitors with high energy and power density

“…6,7 LIBs have higher energy density, 8,9 but cannot meet the demand of high power density. 10 On the contrary, EDLCs have higher power density, 11,12 but cannot be sufficient to meet the demand of high energy density. 13 Hybrid lithium-ion capacitors (LICs) have become the most viable alternative.…”