Increasing the performance of an anion-exchange membrane electrolyzer operating in pure water with a nickel-based microporous layer

Abstract

It has been technologically challenging to create an anion-exchange membrane water electrolyzer (AEMWE) that can operate efficiently without liquid electrolytes, that is, in pure water. Prior improvements in AEMWE have been limited to the development of membranes and catalysts. Here, we report an alternative solution to increase the AEMWE performance from a different perspective by developing highly conductive, macroporous layers (MPLs) as multifunctional liquid/gasdiffusion layers (LGDLs).

Overall design of novel 3D-ordered MEA with drastically enhanced mass transport for alkaline electrolyzers

“…It is preferable to operate alkaline electrolyzers with pure water instead of alkaline electrolytes to avoid electrolyte-induced corrosion. 40 Compared to alkaline electrolytes, the great CL/ML interface is extraordinarily necessary to achieve high-performance pure-water-fed alkaline electrolyzers. As a type of ion-solvating membranes, PBI membranes seldom provide intrinsic hydroxide conductivity in pure water.…”

Construction of Integrated Electrodes with Transport Highways for Pure‐Water‐Fed Anion Exchange Membrane Water Electrolysis

“…EIS can be distinguished into ohmic resistance ( R s ), activation resistance ( R act ), and mass‐transfer resistance ( R m ). [ 36 ] As shown in Figure 4b, the ohmic resistance decreases as ionomer content in IEs increases, which can be attributed to the enhanced hydroxide ion transfer in the CL. [ 20 ] In contrast, the effects of ionomer on R s are negligible when pure water is replaced by the alkaline solution (1 M KOH).…”

Oxygen Evolution Reaction in Alkaline Environment: Material Challenges and Solutions

“…[ 150 ] Until now, Ni (or Ni alloy) coated steel is still the most widely‐used electrode for liquid alkaline electrolyzers due to their high OER activity and stability. [ 151,152 ]…”

“…Except for the CCS configuration, CCM consisting of Acta 3030 (CuCoO x ) catalyst Sustainion membrane (hydroxide ion exchange membrane) also delivered an improved activity for AEMWE. [ 151 ] Besides, the performance degradation issue might be more complicated in AEMWE. The anode catalyst suffers from surface evolution, oxidation, leaching, etc., and in addition, the leached metal ions from the anode can migrate through the electrolyte and then be redeposited on the cathode, likely lowering the activity of the cathodic HER.…”

“…[150] Until now, Ni (or Ni alloy) coated steel is still the most widelyused electrode for liquid alkaline electrolyzers due to their high OER activity and stability. [151,152] Another important electrolyzer cell is the AEMWE (as illustrated in Figure 9B) which has several unique advantages, [153,154] for example, high energy efficiency, producing high purity hydrogen, no high-concentration alkaline electrolyte, corrosionresistance, using low-cost steel bipolar plates, and NPMCs. To integrate with the catalyst, there are two principal approaches to fabricate the membrane electrode assemblies (MEAs) for the AEMWE, namely catalyst-coated substrate (CCS) and catalyst-coated membrane (CCM).…”