Electrical conductivity enhancement of chopped carbon fiber-reinforced epoxy composite bipolar plate for proton exchange membrane fuel cells

Abstract

This study investigated the development of chopped carbon fiber (CCF)-reinforced epoxy (EP)/graphite (G) composite bipolar plates (BPs) using a one-step compression molding process. The primary objective was to fabricate CCF-reinforced EP/G BPs to enhance their electrical conductivity performance by evaluating the electrical conductivity and compactness of the plate among expanded graphite (EG), carbon black (CB) Vulcan, a combination of EG and CB Vulcan, and CB Ensaco. The results indicated that the EG exhibited the highest electrical conductivity of 9.3 S cm⁻¹ and compactness due to the low surface area. Consequently, CCF-reinforced EP/G/EG was selected for further optimization using response surface methodology (RSM) to analyze the parameters of EG composition, CCF composition, and temperature for optimizing electrical conductivity and porosity. The optimum conductivity and porosity of the CCF-reinforced EP/G/EG reached 22.7 S cm⁻¹ and 9.84% with EG composition, CCF composition, and temperature of 7.56 wt.%, 6.63 wt.%, and 186°C, respectively. After optimization, EP/G/EG was connected to a circuit to light up a bulb. It showed a substantial improvement in illumination compared with the samples before optimization. Therefore, the use of CCF-reinforced EP/G/EG with one-step compression molding has proven highly successful for converting energy in renewable energy applications, showcasing exceptional performance.