Construction of Novel Proton Transport Channels by Triphosphonic Acid Proton Conductor-Doped Crosslinked mPBI-Based High-Temperature and Low-Humidity Proton Exchange Membranes

Abstract

High proton conductivity and sufficient stability of the polybenzimidazole membrane are important for the application of high-temperature proton exchange membrane fuel cells (HT-PEMFCs). A series of composite membranes based on crosslinked mPBI (cPBI) with cerium 2,4,6-triphosphono-1,3,5-triazine (CeTPT) were resoundingly fabricated. Novel cPBI networks with tetrafunctional N,N,N′,N′-tetraglycidyl-4,4′-diaminodiphenylmethane (TGDDM) were synthesized. It is noteworthy that a new high-temperature proton conductor CeTPT was added. CeTPT contained three phosphonic acid groups, which offered good proton conductivity at moderate-to-low humidity and had good thermal stability. Tetrafunctional crosslinker TGDDM had multiple functional groups. With a relatively low crosslinking degree (CLD), the mechanical properties, dimensional stability, and oxidative resistance of the membranes were efficiently improved. The low CLD and good physicochemical stability also allowed high doping levels of CeTPT (up to 50%) and consequently high proton conductivity. At 180 °C and 50% RH, the proton conductivity of cPBI-5-CeTPT-50 and cPBI-10-CeTPT-50 was 0.072 and 0.068 S cm–1, respectively. The cPBI-CeTPT membranes showed good methanol resistance and membrane selectivity, and thus the membranes were suitable for direct methanol fuel cells.

A phosphonated phenol-formaldehyde-based high-temperature proton exchange membrane with intrinsic protonic conductors and proton transport channels

“…Compared with pure PBI, the PPF/PBI membranes exhibit higher residual weight percentages, indicating that the interaction between -PO 3 H 2 and imidazole N-H groups could protect the membrane from free radical attack and thus improve its antioxidant stability. 22,26…”

Advancements of Polyvinylpyrrolidone‐Based Polymer Electrolyte Membranes for Electrochemical Energy Conversion and Storage Devices

“…HT‐PEMFC is a kind of PEMFC that works at higher temperatures (130–200 °C) [25b,33] . Compared with traditional LT‐PEMFC, it has obvious advantages, such as facilitating electrode reactivity, improving catalyst resistance to poison, and simplifying the hydrothermal management system [25d,33,34] . As the core component of HT‐PEMFCs, HT‐PEMs have a great influence on the output performance and stability of fuel cells.…”

Structural architectures of polymer proton exchange membranes suitable for high-temperature fuel cell applications

“…Cerium 2,4,6-triphosphono-1,3,5-triazine (CeTPT), a triphonic acid proton conductor, is introduced into the PBI membrane. The CeTPT/PBI membrane shows high proton conductivity at high temperature/low humidity [192]. As one of the most attractive heteropolyacids, phosphotungstic acid (H 3 PW 12 O 40 , HPW) can be used as the proton conductor to improve proton conductivity…”