Enhanced electrochemical performance and long-term durability of composite membranes through a binary interface with sulfonated unzipped graphite nanofibers for polymer electrolyte fuel cells operating under low relative humidity

Ae Rhan Kim, Vinothkannan Mohanraj, Shanmugam Ramakrishnan, Byung-Hyun Park, Myung-Kwan Han, Dong Jin Yoo

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53 Citations (Scopus)

Abstract

The phenylsulfonic-acid functionalized, and unzipped graphite nanofiber (SO3H-UGNF) was studied as a potential proton-conductive material to embed in a sulfonated poly(ether ether ketone) (SPEEK) to create proton exchange membrane (PEM) for polymer electrolyte fuel cell (PEFC) working under low relative humidity (RH). First, we used ammonium fluoride as an unzipping agent to adapt GNF to UGNF, and then functionalized UGNF with 4-benzene diazonium sulfonate to obtain SO3H-UGNF. Subsequently, we prepared a nanohybrid membrane by integrating SO3H-UGNF in SPEEK at 0.1, 0.5, 1, and 1.5 wt%. Compared to SPEEK alone, SPEEK/SO3H-UGNF demonstrated higher water uptake, ion exchange capacity, water sorption, wettability, thermal stability, and tensile strength. The optimized SPEEK/SO3H-UGNF (1 wt%) showed the improved physicochemical, thermal, and tensile properties. This nanohybrid membrane also showed excellent proton conductivity under 20% RH at 90 °C, which is 2.1 times better than SPEEK membrane. When applied as a PEM in a PEFC operating under 20% RH at 60 °C, the maximum power density and durability of SPEEK/SO3H-UGNF (1 wt%) membrane was higher than SPEEK membrane. After durability operation, it also demonstrated better morphological integrity. This study affords valuable insights on SPEEK-based nanohybrid membrane fabrication and optimization for PEFC operating under low RH condition.
Original languageEnglish
Article number153407
Number of pages13
JournalApplied Surface Science Advances
Volume593
Early online date15 Apr 2022
DOIs
Publication statusPublished - 15 Aug 2022
Externally publishedYes

Funder

This research was supported by Basic Science Research through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2021R1I1A1A01050905). This work was supported by grants from the Medical Research Center Program (NRF‐2017R1A5A2015061) through the National Research Foundation (NRF), which is funded by the Korean government (MSIP). This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (NRF-2020R1A2B5B01001458).

Keywords

  • SPEEK
  • SO3H-UGNF
  • Low humidity operation
  • Electrochemical performance
  • Durability

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