Carbon nanotube (CNT) modified carbon fiber/epoxy composite plates for the PEM fuel cell bipolar plate application Fatih Darıcık a,* , Alparslan Topcu a,b , Kadir Aydın b , Selahattin C ¸ elik c a Alanya Alaaddin Keykubat University, Rafet Kayıs ‚ Faculty of Engineering, Department of Mechanical Engineering, Antalya, 07425, Turkey b C ¸ ukurova University, Faculty of Engineering, Department of Automotive Engineering, Adana, 01330, Turkey c Ankara Yıldırım Beyazıt University, Department of Mechanical Engineering, 06010, Ankara, Turkey highlights  120 S/cm electrical conductivity was achieved with the 1.25% CNT reinforcement.  CNTs can increase the flexural strength of the BP up to 42%.  CNTs can increase the flexural modulus of the BP up to 27%.  CNT-modified BP was executed pretty close performance compared to the AA 3105. article info Article history: Received 17 June 2022 Received in revised form 8 September 2022 Accepted 29 September 2022 Available online 22 October 2022 Keywords: PEM fuel cell Composite Bipolar plate MWCNT Flexural Performance tests abstract Light structures of the composite materials are prominent outcomes for reducing the total stack weight. However, the poor electrical properties of the composite structures pose an obstacle to wide employment as a bipolar plate for the PEMFC systems. In the current study, the carbon fiber/epoxy composite laminates were modified with the multi-walled carbon nanotube superconductor materials to overcome conductivity issues. The effects of CNTs additives in a range of 0.25e1.25% wt on the electrical, mechanical, and perfor- mance features of the carbon fiber/epoxy laminates were investigated. Electrical conduc- tivities of the nonconductive carbon fiber/epoxy plates increased with the rising additive ratio, as expected, and reached 120 S/cm for the 1.25% CNT reinforcement. Although the mechanical strength of the pristine composite BP is already satisfactory, CNTs can increase the flexural strength and flexural modulus of the BP up to 42% and 27%, respectively. Each composite plate was subjected to the single-cell performance test. 1.25% wt CNT modified plate was executed pretty close performance compared to the aluminum alloy (AA 3105) bipolar plate under the same conditions. © 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. * Corresponding author. E-mail addresses: fatih.daricik@alanya.edu.tr (F. Darıcık), alparslan.topcu@alanya.edu.tr (A. Topcu), kdraydin@gmail.com (K. Aydın), selahattincelik@aybu.edu.tr (S. C ¸ elik). Available online at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/he international journal of hydrogen energy 48 (2023) 1090 e1106 https://doi.org/10.1016/j.ijhydene.2022.09.297 0360-3199/© 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.