Polymer fuel cells based on polybenzimidazole/H3PO4

Abstract

Polybenzimidazole-based membranes are nowadays considered the best alternative to NafionÒ for the fabrication of high-temperature polymer fuel cells. The rich chemistry of benzimidazole allows us to widely change the physicochemical properties of the resulting polymers and, consequently, to tune the functional properties of the electrolyte membrane. In this perspective we report the most recent developments in PBI-based membranes, cells and stacks. Emphasis is given to problems such as acid leaching, membrane degradation and stack durability.

Epoxides cross-linked hexafluoropropylidene polybenzimidazole membranes for application as high temperature proton exchange membranes

“…Up to now, the most promising electrolytes for the high temperature PEMFCs are widely considered as phosphoric acid (PA) doped polybenzimidaozle (PBI) membranes, just as stated in the DOE Fuel Cells Technical Plan of 2012 [3,4]. The advantages of the PBI-based PEMFCs include working under low humidity conditions, high CO tolerance, better heat utilization and possible integration with fuel processing units [1,5]. The PBI is a kind of heterocyclic polymers with excellent thermal and mechanical properties.…”

High‐Temperature Polymer Electrolyte Fuel Cell Using Poly(vinylphosphonic acid) as an Electrolyte Shows a Remarkable Durability

“…[4] High-temperature PEMFCs using the PA-doped system in the membrane and the catalyst layers (Cat-L) have already been reported to show a good performance at low-humidity conditions. [5] However, recent studies of the PA-doped PBI systems have revealed the leaching of PA from the membrane because it is a liquid [6] and affect the stability of the proton conduction in the cell, [7] which results in the deterioration of performance during a long-term operation. To solve this problem, there is a tremendous demand to assemble a highly proton conducting cell with a proton leaching-free property at high operating temperatures to improve the durability of PEMFCs.…”

Exceptional durability enhancement of PA/PBI based polymer electrolyte membrane fuel cells for high temperature operation at 200 °C

“…1 Membranes of phosphoric acid (PA) doped polybenzimidazole (PBI, Scheme S1, ESI †) [2][3][4] or pyridine containing aromatic polyethers 5 are among the most promising electrolyte systems in this connection, showing high proton conductivity at low water activity as well as good thermal and oxidative stability. Great progress has been achieved in this field and lifetimes of up to 18,000 h have been reported by several groups at constant current load as well as under dynamic operation at intermediate temperatures up to about 160 °C.…”