A review of the porous transport layer in polymer electrolyte membrane water electrolysis

Abstract

Polymer electrolyte membrane water electrolysis (PEMWE) is the most promising and environmentally friendly method for highly pure hydrogen production when integrated into renewable energy sources. Presently, water electrolysis has merely 4% contribution to global hydrogen production owing to its economic challenges. To reduce the capital and operational cost of PEM water electrolysis, the porous transport layer (PTL) has been investigated intensively in the recent past. A PTL, sandwiched between a catalyst layer and a flow field, is responsible to transport water and oxygen on the anode side as well as hydrogen on the cathode side. In addition to the role of multiphase fluid transportation, PTL also acts as a current collector. A comprehensive insight into PTL materials, structural properties, and their function is strongly required for researchers to enhance performance and reduce the cost of PEMWE system. In this review, we widely discussed the findings on PTL's structural properties, surface modifications, and their impact on enhancing electrochemical performance and durability. In particular, the effect of pore size, porosity, pore gradient, thickness, and pretreatment on ohmic, mass transport, activation overpotential, and PTL modeling has been intensively analyzed. This review will unequivocally increase the previous understanding and open up an avenue for the development of state-of-the-art PTL, thereafter advancing the commercialization of PEMWE.

Layered double hydroxide composite membrane for advanced alkaline water electrolysis

“…Proton exchange membrane (PEM) water electrolyzer has a compact system structure and can operate stably for a long time with high current density (>1 A cm −2 )， producing higher purity hydrogen (>99.99%), higher gas production pressure (3‐4 MPa), and faster dynamic response speed, as well as adapting adapt to fluctuations in renewable energy power generation 14,15,22,23 . However, the high cost of Ir‐based noble metal‐oxygen evolution electrocatalysts and bipolar plates used in a PEM electrolyzer limits the large‐scale commercial process of PEM water electrolysis 24–28 …”

“…14,15,22,23 However, the high cost of Ir-based noble metal-oxygen evolution electrocatalysts and bipolar plates used in a PEM electrolyzer limits the large-scale commercial process of PEM water electrolysis. [24][25][26][27][28] Alkaline water electrolysis was the most skillful hydrogen production technology with a long history. 29,30 It can use non-precious metals as catalysts and cheap asbestos mesh as the diaphragm between the cathode and anode of the electrolyzer, giving alkaline water electrolysis a significant low-cost advantage.…”

Effect of pore structures in nickel‐based porous transport layers for high‐performance and durable anion‐exchange membrane water electrolysis

“…Thus, researchers have invested tremendous efforts in enhancing its performance and durability by developing various components, such as AEMs, 6 electrocatalysts, 7 and porous transport layers (PTLs). 8 The PTL is a crucial component that influences electron and mass transfer in the AEMWE. 8 Since the PTL transports the electrons necessary for electrochemical reactions, an electrically conductive material should be used.…”

“…8 The PTL is a crucial component that influences electron and mass transfer in the AEMWE. 8 Since the PTL transports the electrons necessary for electrochemical reactions, an electrically conductive material should be used. In addition, a highly porous structure is required because it plays an important role in supplying reactants to the entire catalyst layer and removing the products generated in that layer with the bipolar plate.…”

3D two‐phase and non‐isothermal modeling for PEM water electrolyzer: Heat and mass transfer characteristic investigation

“…Proton exchange membrane (PEM) water electrolyzer is being recognized as promising hydrogen production technology, 1,2 due to high current density, high purity hydrogen production, fast response, and non-corrosive electrolyte. 3,4 Despite these advantages, the large-scale application of the PEM water electrolyzer at present is limited by the price and particularly durability.…”