Effect of PTFE loading of gas diffusion layers on the performance of proton exchange membrane fuel cells running at high-efficiency operating conditions

Abstract

SUMMARYIn this paper, the effects of microporous layer (MPL) addition and polytetrafluoroethylene (PTFE) loading of gas diffusion layers (GDLs) on the overall performance of the proton exchange membrane fuel cell have been investigated. The focus was on fuel cells that operate at relatively low current densities where the power demand is low, but the efficiency is of concern. The results show that, in the activation loss-controlled region, the performance of the fuel cell operating with moderately PTFE-treated carbon substrates is superior over that operating with coated GDLs. This is due to the addition of the MPL which lengthens the diffusion paths and significantly reduces the mass transport properties. Conversely, in the ohmic loss-controlled region, the fuel cell with coated GDLs performs better than those with carbon substrates. This is explained by the enhanced contact of the GDL with the adjacent components after the MPL addition, which outweighs the negative effects associated with the activation loss-controlled region. Also, it was found that the fuel cell performance becomes lower if the GDL is treated with a relatively high PTFE loading in either the carbon substrate (due to the decrease in the porosity of the GDL) or the MPL.

Compress effects on porosity, gas-phase tortuosity, and gas permeability in a simulated PEM gas diffusion layer

“…This value falls approximately in acceptable compression ratios according some experimental and numerical studies previously performed [20,21]. In this model, the final thickness after several compression steps was established in 66% of the initial thickness.…”

The effects of the composition of microporous layers on the permeability of gas diffusion layers used in polymer electrolyte fuel cells

“…Isopropyl alcohol was added to the formed mixture and the resulting slurry was placed in an ultrasonic bath (U300H, Ultrawave Ltd, UK), with a power 35 W, until an ink with a good dispersion was formed. Using nitrogen, the ink was then manually sprayed onto the samples of the carbon substrates attached to a heated plate [22].…”

“…As shown in Fig. 1, the setup consists of upper and lower fixtures, with the sample fixed between the two fixtures as described in [22]. Nitrogen flows through the sample and the pressure drop across the sample was measured at 7 equally- …”

“…As stated earlier, the literature has shown that the permeability of the GDL increases with increasing PTFE loading in the MPL [21][22]. However, such a results was drawn from either a single value for the carbon loading and/or a limited number of PTFE loadings.…”

Proton Exchange Membrane Fuel Cell Reversal: A Review

“…Obviously, there are still several problems in need of further study, such as (1) understanding the effects of different types of carbon materials' surface forms and structure; (2) developing a novel Numerous research papers have studied the effect of hydrophobic agent content and species, including polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and fluorinated ethylene propylene (FEP), in GDL on the performance of fuel cells [73][74][75]. Given their excellent characteristics, hydrophobic agents can be used in the anode catalyst layer to hold more water.…”