Gas diffusion layer from Binchotan carbon and its electrochemical properties for supporting electrocatalyst in fuel cell

Abstract

The gas diffusion layer (GDL) in the fuel cell has been made from carbon dispersion electrochemically deposited from binchotan. We prepared GDL by spraying the ink on the surface of the conductive paper. The carbon was then characterized by its crystallography, surface functional groups and size by x-ray diffraction (XRD), FT-IR and PSA instrumentations. Cyclic voltammetry and impedance spectroscopy tests were applied to study the GDL electrochemical characters. Buble drop tests were used to obtain contact angles representing the hydrophobicity of the layer. The electrodeposition/oxidation of binchotan derived carbon dispersion has a crystalline phase in its dot structure. According to particle size analysis, carbon dispersion has an average particle size diameter of 176.7 nm, a range of 64.5–655.8 nm, and a polydispersity index was 0.138. The Nyquist plot revealed that the processes in the GDL matrices as the plot consist of two types of structures, i.e., semicircular curves and vertical (sloping) lines. The GDL electrical conductivity of Vulcan and carbon dots were 0.053 and 0.039 mho cm-1. The contact angle between conductive paper and water was 150.27°; between the gas diffusion layer and carbon Vulcan was 123.28°, and between the gas diffusion layer and carbon dispersion was 95.31°. The surface of the GDL with Vulcan is more hydrophobic than that made with carbon dispersion. In other words, the GDL with carbon dispersion is closer to hydrophilic properties. The results show that the carbon can support the gas diffusion layer for hydrophobic and hydrophilic conditions.