Experimental study and analytical modeling of an alkaline water electrolysis cell

Abstract

Summary A traditional alkaline aqueous electrolyzer is investigated by using a 3‐electode structure that enables the reaction resistance of each individual electrode to be accurately monitored. Combining experimental observations with resistance‐based model analysis, we establish a quantitative relationship between current density and key voltage losses, including losses due to thermodynamics, kinetics, ohmic, and mass transport. These results demonstrate that the oxygen evolution reaction and bubble effects play crucial roles in determining electrolyzer performance. By varying the distance between electrodes, 2 effective OH− conductivities in 0.4M KOH are found to be 0.1333 and 0.9650 second cm−1, depending on bubble formation and release rate at the electrode interface. Moreover, bubble coverage on electrode surface achieves a steady state of 96% when current density is above 0.1 A cm−2. In the study of various electrolyte concentrations, all the model predictions show good agreement with experimental results, confirming its ability to capture actual cell performance. This newly presented empirical resistance‐based model provides a practical framework to simulate complicated electrolysis reactions, serving as a comprehensive guide for continuous improvement of water electrolysis.

Fabrication of FeO@CuCo 2 S 4 multifunctional electrode for ultrahigh‐capacity supercapacitors and efficient oxygen evolution reaction

“…However, their low scarcity and high cost have prevented them from being used for practical applications. [21][22][23][24][25] Thus, the invention of inexpensive and high-performance OER electrocatalysts consisting of earthabundant materials is essential to substitute precious metal oxide catalysts.…”

Mathematical modeling and simulation for external electrothermal characteristics of an alkaline water electrolyzer

“…(1) P start in the jth range (1 ≤ j ≤ N) j ¼ ceil P start −P e min step (23) (2) P start + ΔP in the kth range (1 ≤ k ≤ N) k ¼ ceil P start þ ΔP−P e min step (24) (3) P Tmax (T start ) corresponding to the starting temperature T start in the lth range (1 ≤ l ≤ N, j ≤ l ≤ k) l ¼ ceil P T max T start ð Þ−P e min step (25) Let the starting value of P Tmax in the ith phase be P Tmaxi1 , the corresponding starting temperature be T i1 , the ending value of P Tmax be P Tmaxi2 , and the corresponding ending temperature be T i2 . The starting temperature of the first phase is represented by T start , and the ending temperature of the last phase is represented by T end .…”

“…It further affected the excitation overpotential, concentration difference potential, and ohm potential of the electrolyzer and, through test and simulation studies, the influence of temperature on the I‐V curve of the electrolyzer was analyzed. A quantitative relationship between current density and critical voltage loss was established in Chen et al based on experimental results and analytical modeling methodologies, which include thermodynamic, kinetic, ohmic, and mass transfer losses. The results indicate that the oxygen evolution reaction and bubble effect play a key role in determining the cell performance.…”

NiSFeS/N, S co‐doped carbon hybrid: Synergistic effect between NiS and FeS facilitating electrochemical oxygen evolution reaction

“…Oxygen evolution reaction (OER) is one of the key reactions in electrochemical water splitting, which has been considered as an efficient technology to produce hydrogen energy 1,2 . However, the kinetics in OER are so slow that the overpotential is very high, leading to huge electricity consumption 3 . Hence, it is necessary to explore appropriate OER electrocatalysts to accelerate the overall water splitting and facilitate its industrialization.…”