Structure and Properties of Carboxylated Carbon Nanotubes@Expanded Graphite/Polyethersulfone Composite Bipolar Plates for PEM

Abstract

Composite bipolar plates (BPs) hinder their application in proton exchange membrane fuel cells (PEMFC) because of their poor conductivity and mechanical properties. Nanofillers can effectively solve this problem but often have a limited effect due to their easy agglomeration. In this work, a continuous mesh carboxylated multi-walled carbon nanotube (MWCNT) coating on the surface of graphite was synthesized by chemical vapor deposition (CVD) and carboxylation modification, and the composite BPs were prepared by molding using prepared reticulated carboxylated MWCNTs, expanded graphite, and resin. By optimizing the carboxylation treatment time and the content of the nano-filler, the composite BPs had the best performance at a 15 min carboxylation treatment time and 2.4% filler content. The planar conductivity reached up to 243.52 S/cm, while the flexural strength increased to 61.9 MPa. The thermal conductivity and hydrophobicity were improved compared with the conventional graphite/resin composite BPs, and good corrosion resistance has been demonstrated under the PEMFC operating environment. This work provides a novel nanofiller modification paradigm for PBs.

Progress of bipolar plates for proton exchange membrane fuel cells

“…For the newnanofiller modification, 2023 Li [6] in synthesized a continuous reticulated carboxylated multi-walled carbon nanotube (MWCNT) coating on the surface of expanded graphite using chemical vapor deposition (CVD) and carboxylation modification, and prepared composite bipolar plates by moulding using reticulated carboxylated MWCNT, expanded graphite and resin. By optimising the carboxylation treatment time and nanofiller content, the composite bipolar plates had the best performance at a carboxylation treatment time of 15 min and a filler content of 2.4%.…”

Progress in the study of bipolar plates/conductive fillers

“…In addition, after the addition of MWCNTs, due to the presence of the conductive network, the conductivity of the composite bipolar plate containing 5 wt% MWCNTs and 35 wt% graphite was further reduced to 161.57 S /cm, with a flexural strength of 42.65 MPa and a corrosion current density of less than 1 μA/cm2 . Li et al [20] prepared reticulated carboxylated MWCNT, expanded graphite and resin were molded to prepare composite bipolar plates. The experimental results showed that when the carboxylation treatment time was 15 min and the filler content was 2.4%, the planar conductivity reached 243.52 S/cm and the flexural strength reached 61.9 MPa.Unlike the conventional composite bipolar plates with directly added MWCNTs, the carboxylated MWCNTs dispersed more homogeneously and the wettability with the resin was significantly improved.…”