Study on Separator for Alkaline Water Electrolysis. Issue 11 (3rd August 2016)

• Record Type: Journal Article
• Authors: Manabe, Akiyoshi; Domon, Hiroki; Kosaka, Junko; Hashimoto, Terumi; Okajima, Takeyoshi; Ohsaka, Takeo
• Is Part Of: Journal of the Electrochemical Society. Volume 163:Issue 11(2016)
• Page Start: F3139
• Page End: F3145
• Publication Date: 2016-08-03
• Subjects: alkaline water electrolysis -- anode -- cathode -- separator -- zero gap cell; Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/2.0191611jes
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : The performance of separators of ion-exchange membrane (IEM) and diaphragm types in the zero-gap system of alkaline water electrolysis (AWE) was examined using different sizes of cells (i.e., 20, 100 and 1600 cm 2 ). The optimum KOH concentrations for AWE were found to be ca.15 and 25–30 wt% for IEM and diaphragm, respectively, which are different from the KOH concentration (ca. 35 wt% at 80°C) at which the maximum conductivity is obtained. It was confirmed that only anode side feeding operation is available without any serious mixing of both anolyte and catholyte using 1600 cm 2 pilot-cell under ca 2.94 kPa differential pressure, typically, the cell voltage of 1600 cm 2 pilot-cell was 1.81 V at 0.4 A/cm 2 and 82°C with hydrogen purity of 99.96%. The flow rate of electrolyte does not dominate the purity of hydrogen gas produced. The fluctuation of cell voltage in the diaphragm-based AWE process is very large, suggesting that the quality and/or pretreatment of diaphragm dominate the performance of AWE. It was also confirmed that the diffusion amounts through the diaphragm as gas and dissolved species are on the same level.