Thin Film Composite Membranes as a New Category of Alkaline Water Electrolysis Membranes

Abstract

Alkaline water electrolysis (AWE) is considered a promising technology for green hydrogen (H2) production. Conventional diaphragm‐type porous membranes have a high risk of explosion owing to their high gas crossover, while nonporous anion exchange membranes lack mechanical and thermochemical stability, limiting their practical application. Herein, a thin film composite (TFC) membrane is proposed as a new category of AWE membranes. The TFC membrane consists of an ultrathin quaternary ammonium (QA) selective layer formed via Menshutkin reaction‐based interfacial polymerization on a porous polyethylene (PE) support. The dense, alkaline‐stable, and highly anion‐conductive QA layer prevents gas crossover while promoting anion transport. The PE support reinforces the mechanical and thermochemical properties, while its highly porous and thin structure reduces mass transport resistance across the TFC membrane. Consequently, the TFC membrane exhibits unprecedentedly high AWE performance (1.16 A cm−2 at 1.8 V) using nonprecious group metal electrodes with a potassium hydroxide (25 wt%) aqueous solution at 80 °C, significantly outperforming commercial and other lab‐made AWE membranes. Moreover, the TFC membrane demonstrates remarkably low gas crossover, long‐term stability, and stack cell operability, thereby ensuring its commercial viability for green H2 production. This strategy provides an advanced material platform for energy and environmental applications.

A Review of the Recent Advances in Composite Membranes for Hydrogen Generation Technologies

“…The AWE employing composite membranes is reported to improve the physical properties of the membrane separator and thus, to ensure performance enhancement. − In this context, Choi et al prepared a thin film composite membrane for AWE systems . The proposed membrane was prepared by the formation of of an ultrathin quaternary ammonium selective layer on a porous polyethylene support (Figure a).…”

“… 101 − 104 In this context, Choi et al prepared a thin film composite membrane for AWE systems. 103 The proposed membrane was prepared by the formation of of an ultrathin quaternary ammonium selective layer on a porous polyethylene support ( Figure 3 a). The favorably anion-conductive quaternary ammonium layer supported the prevention of gas crossover and the resulting alkaline-stable membrane resulted in an AWE performance of 1.16 Acm –2 (@1.8 V, 80 °C) using nonprecious group metal electrodes with a aqueous solution of KOH (25 wt %).…”

“… (a) Schematic representation for an AWE cell and composite membrane production steps (reproduced with permission from ref ( 103 ), Copyright 2024 John Wiley and Sons. ), Zirconia/Polysulfone composite membrane with cellulose nanocrystals; (reprinted with permission from ref ( 101 ), Copyright 2021 Elsevieer B.V.), (b) cross-sectional SEM image, (c) cell performance of alkaline cells with 10 wt % KOH, (d) the preparation process of MEA based on PTFE/LDH composite membranes by pore-filling method, (e) and schematic illustration of the designed AWE (reprinted with permission from ref ( 104 ), Copyright 2021 Elsevier B.V.).…”

Best Practices in Membrane Electrode Assembly for Water Electrolysis

“…Lee et al prepared a thin film composite (TFC) membrane with an ultrathin dense layer of quaternary ammonium (QA) over a porous polyethylene (PE) support synthesized using Menshutkin-reaction-based interfacial polymerization (Table 1). 191 For the AWE, the dense and thin layer helped to reduce the mass transport resistance, prevent possible gas crossover, and promote hydroxide ion conductivity. Furthermore, the porous structure also facilitated mass transport across the selective layer-support interface, while maintaining mechanical and thermochemical stability.…”

Highly ion conductive ion solvating membranes for durable alkaline water electrolysis at low temperature and voltage

“…13 Zhang and coworkers reported a series of novel multiblock AEMs (PBPA- b -BPPs), and their AEMWE devices showed a current density of 6.25 A cm −2 at 2.0 V, 80 °C, along with excellent in situ stability over 3200 h. 14 Lee and coworkers proposed a new category of AWE membranes; this was a thin film composite (TFC) membrane consisting of an ultrathin quaternary ammonium (QA) selective layer formed via the Menshutkin reaction-based interfacial polymerization on a porous polyethylene (PE) support. 15 However, compared to state-of-the-art PEMWE, AEMWE still displays inferior performance and limited lifetime, probably owing to the low conductivity and instability of AEMs under alkaline conditions. As an alternative approach, ion-solvating membranes (ISMs) have recently attracted considerable attention in the application of alkaline water electrolysis.…”