High temperature proton exchange membrane fuel cells: progress in advanced materials and key technologies

Abstract

This comprehensive review gives a picture about the state-of-the-art progress of HT-PEMFCs, and the challenges, strategies and rules to design, evaluate and promote the performance of HT-PEMFCs.

Diffusivity and free anion concentration of ionic liquid composite polybenzimidazole membranes

“…5,6 In the continuous search to develop low-cost PEMs with high conductivity at elevated temperatures, the use of non-peruorinated polymers has experienced a blooming along the past decades. [7][8][9][10][11][12][13] Among the different non-peruorinated membranes, polybenzimidazole (PBI) has emerged as an attractive alternative to replace Naon membranes due to its lower methanol crossover as well as higher thermal and mechanical stability. 14 Additionally, when doped with phosphoric acid, PBI membranes have shown conductivities around 0.1-0.2 S cm À1 at elevated temperatures.…”

A Review of Recent Developments and Advanced Applications of High-Temperature Polymer Electrolyte Membranes for PEM Fuel Cells

“…The PEM has a vital role in a fuel cell assembly by performing various functions such as being a carrier path for proton transport from the anode to the cathode side, a dense separation layer to block the mixing of the reactants, and an electric insulation layer between the anode and cathode. Many studies in the past few years have reported the enhancement of various functions of PEMs [26][27][28][29][30]. One of the key objectives for the PEMs' development is to reduce the cells' total fabrication cost and improve their electrochemical performance and durability [31,32].…”

“…The main drawbacks associated with PA are membrane degradation and catalyst poisoning due to the harsh operating conditions and unfavourable electrochemical reactions as well as acid leaching. Thereby, the highest performance can be achieved by optimising the acid-doping level (ADL) or other strategies such as covalent crosslinking or making composite PEMs [28]. Depending on the ADL, PA can be classified into two general groups: "bonded acid" and "free acid".…”

“…In the past couple of decades, the LT-PEMs fuel cells operation has received great attention to improve their CO tolerance level, lower the use of precious metals, better heat and water management, facilitate the electrode reaction kinetics, and gain higher electrochemical performance. Currently, the main focus of the HT-PEMs research and development community is to control the high degradation rate of PEMs, long start-up and shutdown procedures, and the cell durability at higher temperatures [28,112,113]. Table 1 compares the main factors affecting the operation of the LT-PEMs and HT-PEMs.…”

A Review on Ionic Liquids-Based Membranes for Middle and High Temperature Polymer Electrolyte Membrane Fuel Cells (PEM FCs)

“…It also can result in facilitating heat and water management [ 10 ]. A wide range of investigations have been conducted by researchers for finding new other electrolyte materials that can be used at middle and high temperatures and under aqueous-free conditions to retain suitable proton conductivity, thermal stability, and mechanical resistance [ 23 , 53 , 56 , 57 ]. Dehydration in PEMFC is the biggest problem here because all of these materials can work under fully moisture condition [ 23 ].…”