Activation of stainless steel 316L anode for anion exchange membrane water electrolysis

Tuning Stainless Steel Oxide Layers through Potential Cycling─AEM Water Electrolysis Free of Critical Raw Materials

“…This performance compares favorably to an Ir-based single-cell AEMWE achieving 1.44 A cm –2 at 2.0 V, 55 °C, thereby showcasing the great activity of potential cycled 316L SSF anodes over costly, traditional PGM catalysts. Table S2 compares the reported single-cell performances against other non-CRM AEMWEs, placing the reported values in the forefront. ,− Moreover, the simplicity of this activation procedure underlines the importance of the reported work compared against more complicated activation schemes. Polarized EIS spectra shown in the Bode diagram in Figure d indicate a great improvement in the anode performance as the potential is increased, as shown by the large decline in the anode time constant.…”

“…These electrodes were tested in a highly efficient three-electrode setup built to allow for a high degree of reproducibility over many tests. The complete account of this setup is presented in our previous work . The potentials were recorded against a Ag/AgCl (3.0 M KCl) reference electrode and converted to the reversible hydrogen electrode (RHE) through eq shown below. E normalR normalH normalE = E A g / A g C l + 0.059 × p H + E 0 , goodbreak0em2em⁣ E 0 = 0.210 .25em V normalR normalH normalE …”

“…As such, complete removal of Cr likely requires KOH concentrations significantly higher than the typical 1.0 M KOH employed in AEM water electrolyzers, as Zamanizadeh et al 10 still noted Cr oxide layers for KOH electrolytes up to 5.5 M. Moreover, applied potentials are also required, as little change in the bulk composition of an unpolarized was noted after prolonged exposure to the 1.0 M KOH electrolyte as shown in Figure S13c. This change in surface oxide composition is determined by the solid-state diffusion coefficients of Fe, Ni, and Cr (Fe > Ni ≫Cr) 25 and the bulk composition. As such, investigating the subsurface for the three different EPC durations will yield valuable information on the formation of the oxide layers formed on SS substrates.…”

“…These three facets significantly amplify its potential as an OER electrode if a fair catalytic activity is achieved and sustained over time. Such electrodes are initially inactive toward the OER, although potential cycling has been shown to increase its catalytic activity through the formation of a catalytically active oxide layer. ,,, This has previously been performed on both 2D solid SS electrodes ,, and 3D porous SS felt (SSF) electrodes. , However, the impact of potential cycling conditions, such as the cycling rate and potential range, is unknown together with their influence on the oxide layer, its composition, and resulting catalytic activity/stability.…”

Accelerating Hydrogen Desorption of Nickel Molybdenum Cathode via Copper Modulation for Pure‐Water‐Fed Hydroxide Exchange Membrane Electrolyzer

“…Whereas the R p decreases clearly from the NiFeOOH(F)//Pt/C HEMEL to the NiFeOOH(F)//Ni 0.9 Cu 0.1 Mo HEMEL, representing a lower charge transfer resistance for Ni 0.9 Cu 0.1 Mo cathode than Pt/C cathode. [ 40 ] Moreover, a degradation rate of merely 0.17 mV h −1 over a 100 h period at 500 mA cm −2 illustrates the surprising durability performance of the NiFeOOH(F)//Ni 0.9 Cu 0.1 Mo HEMEL (Figure S29, Supporting Information).…”