Influence of a pore‐former and PTFE in the performance of the direct ethanol fuel cell

Abstract

The direct ethanol fuel cell (DEFC) is a promising fuel cell device, which could provide power to portable and microelectronic equipment in the future. In the present investigation, the influence of a pore-former, polytetrafluoroethylene (PTFE) and catalyst loadings in the electrocatalyst of the anode on DEFC performance is studied. The decal transfer method is used to prepare the membrane electrode assembly (MEA) using Pt-Ru/C (40 : 20% by wt) as the anode catalyst, and Pt/C (40% by wt) as the cathode catalyst, a pore-former, PTFE dispersion and Nafion ionomer. The pore-former used is 10% (by wt) NaHCO 3 in the catalyst ink during the preparation of MEA. The voltage-current characteristics of DEFC were monitored at different loadings of the catalyst, PTFE and a pore-former in MEA. The DEFC performance improved with the use of a pore-former and higher loading of PTFE in MEA. Higher DEFC performance is obtained because PTFE, along with the network of pores in the anode side allowed easy removal of reaction species, thereby rendering the catalyst site available for ethanol oxidation. Further, the use of a pore-former and PTFE at the anode allowed higher loading of electrocatalyst resulting in an increase in the performance of DEFC. The DEFC, with 1 mg cm −2 of catalyst loading at the anode and cathode, 10% (by wt) NaHCO 3 of a pore-former, 20% (by wt) PTFE loading in catalyst ink gives maximum power density of 8.5 mW cm −2 at a current density of 31.3 mA cm −2 .

Effect of operating parameters and anode diffusion layer on the direct ethanol fuel cell performance

“…3, i.e., the kinetic region is not affected by changing the diffusion layer porosity while at higher currents the slope of the curve increases with decreasing porosity. Furthermore, Biswas et al [17] found better performance by increasing both the porosity and the PTFE content (20%) in the catalyst layer. However, in their case the catalyst layer was fabricated using pore formers, therefore the PTFE content could have a very different effect compared to the present work.…”

“…Although the CCM MEA had higher ethanol crossover rate, its performance and stability were superior compared to the GDE MEA, having a peak power degradation of 15% against 34% for the GDE MEA in a 10 h life test, which was attributed to less delamination problems in the case of the CCM MEA. The structure of the catalyst layer has also been investigated for DEFC [17]. In this work, the authors obtained higher cell performance using pore formers in the anode catalyst layer, and by increasing PTFE content in the catalyst layer from 10 to 20 wt%.…”

Model‐based design and optimization of the microscale mass transfer structure in the anode catalyst layer for direct methanol fuel cell

“…NH 4 HCO 3 was also used as a PF in the cathode CL of a DMFC, which improve the cell performance by approximately 30%. The performance enhancement obtained using PFs in a direct ethanol fuel cell was also confirmed by adding 10 wt % NaHCO 3 into the catalyst ink during MEA fabrication . The effect of the PF loading in the anode CL of a DMFC was also investigated .…”

“…Recently, studies have focused on the mass transfer behavior of the reactants inside the electrodes . To improve the mass transfer, pore formers (PFs) were incorporated into the CLs or the microporous layers to improve the performance of the fuel cell. Tucker et al enhanced the maximum power density of an active DMFC from approximately 900 to 1200 W/m 2 by adding 50 wt % Li 2 CO 3 into the anode CL as PF.…”