Anodized Steel Electrodes for Supercapacitors

Abstract

Steel was anodized in 10 M NaOH to enhance its surface texture and internal surface area for application as an electrode in supercapacitors. A mechanism was proposed for the anodization process. Field-emission gun scanning electron microscopy (FEGSEM) studies of anodized steel revealed that it contains a highly porous sponge like structure ideal for supercapacitor electrodes. X-ray photoelectron spectroscopy (XPS) measurements showed that the surface of the anodized steel was Fe2O3, whereas X-ray diffraction (XRD) measurements indicated that the bulk remained as metallic Fe. The supercapacitor performance of the anodized steel was tested in 1 M NaOH and a capacitance of 18 mF cm(-2) was obtained. Cyclic voltammetry measurements showed that there was a large psueudocapacitive contribution which was due to oxidation of Fe to Fe(OH)2 and then further oxidation to FeOOH, and the respective reduction of these species back to metallic Fe. These redox processes were found to be remarkably reversible as the electrode showed no loss in capacitance after 10000 cycles. The results demonstrate that anodization of steel is a suitable method to produce high-surface-area electrodes for supercapacitors with excellent cycling lifetime.

Flexible Polypyrrole@Fe2O3@Stainless Steel Yarn Composite Electrode for Symmetric Thread‐Like Supercapacitor with Extended Operating Voltage Window in Li2SO4‐Based Aqueous Electrolyte

“…In the Fe 2p XPS spectrum (Figure 3c), the peak at 711.1 eV is assigned to Fe 2p 3/2 with its associated satellite at 718.3 eV, meanwhile the peak at 724.6 eV is assigned to Fe 2p 1/2 with its associated satellite at 730.68 eV, which indicate the existence of Fe 2 O 3 . [ 34,36,37 ] As for the survey XPS spectrum of the PPy@Fe 2 O 3 @SSY sample (Figure 3d), the S, C, N, and O elements are present. The presence of S element is due to the dopant sodium p ‐toluenesulfonate, and the absence of Fe element is because of the relatively thick PPy layer covered on the Fe 2 O 3 @SSY.…”

“…[ 33 ] The typical diffraction peaks for Fe 2 O 3 are not obvious, which may be due to the strong background from SSY and the amorphous phase of the as‐prepared Fe 2 O 3 nanosheets. [ 34,35 ] Longer acid corrosion time can achieve higher specific capacitance according to the cyclic voltammetry (CV) and GCD results, but the mechanical strength of Fe 2 O 3 @SSY composite drops dramatically (Figure S2, Supporting Information). Considering the specific capacitance and mechanical strength, the acid corrosion time is determined to be 20 min for preparation of the Fe 2 O 3 @SSY composite in this study.…”

Antibacterial properties of Ag/TiO2/PDA nanofilm on anodized 316L stainless steel substrate under illumination by a normal flashlight

“…Our group has fabricated nanopore arrays on the surface of 316L SS by anodic oxidation [36][37][38]. The use of anodized 316L SS has received considerable attention for increasing the surface areas, because the inert SS with high corrosion resistance are difficultly corroded [39][40][41]. In this study, we have synthesized a three-dimensional (3D) Ag/TiO 2 /PDA nanofilm using Ag-decorated amorphous TiO 2 nanolayer as light harvester and PDA as transformation interface.…”

Timely-activated 316L stainless steel: A low cost, durable and active electrode for oxygen evolution reaction in concentrated alkaline environments

“…The group of Schafer made significant progresses in this direction for OER electrocatalysis [72,74,75], soon followed by others [79], the strategy being also used for alternative applications, e.g. to design supercapacitors [80] or Liion battery [81] electrodes.…”