What is the challenge of anion selective membranes for electrolyzers?
Posted: Wed Jul 25, 2018 8:27 am
Industrial alkaline water electrolysis mainly employs asbestos diaphragm as a separator but this material has high electrical resistance, is carcinogenic (i.e. asbestosis), and is unsuitable for use at temperatures above 100 oC. The struggle is to dismiss the diaphragm-type separator currently used and replace it with novel anion selective membranes. The struggle is to find new materials with stable functional groups against the aggressive KOH electrolyte solution. Besides, these materials need to be highly conducive to OH- ion. A stable and highly conductive anion selective membrane is the key challenge that membrane engineers are facing. The ideal anion selective membrane avoids gas crossover, significantly reduces Ohmic losses and allows the use of low-cost electrodes and catalysts efficiently, even allowing the possibility to operate with pure water. So, can it be found? The search continues.