Design of New MEA Structure for Mciro Direct Methanol Fuel Cell

2013 ◽  
Vol 694-697 ◽  
pp. 1565-1568
Author(s):  
Wen Bin Zhang ◽  
Da Da Wang
Keyword(s):  
Layer Structure ◽  
Catalyst Layer ◽  
Electrode Reaction ◽  
Gas Diffusion ◽  
Cathode Side ◽  
Catalyst Loading ◽  
The Novel ◽  
Anode Side ◽  
Pore Former ◽  
Direct Methanol

A novel double-catalyst layer MEA using CCM-GDE (Catalyst Coated Membrane,CCM;Gas Diffusion Electrode,GDE) fabrication method is provided. The double-catalyst layer is formed with an inner catalyst layer (in anode side: PtRu black as catalyst, in cathode side: Pt black as catalyst) and an outer catalyst layer (in anode side: PtRu/C as catalyst, in cathode side: Pt/C as catalyst). By study of the catalyst loading in the double-catalyst layer, an optimization of the catalyst layer structure is obtained, that is the cell may perform best when the ratio of the inner catalyst and outer catalyst is 1:1 (both in inner and outer catalyst layer, the catalyst loading is 1.5mg/cm2). As the hydrophilicity and pore structure are important to the MEA performance, they are optimized by adding pore former and Nafion in the GDL and outer catalyst layer, respectively. Thus three gradients from the PEM to the GDL are formed in the novel MEA: catalyst concentration gradient, porosity gradient and hydrophilicity gradient. These gradients may increase the mass transfer and quicken the electrochemistry reaction in MEA. The CCM-GDE technology may enhance the contact properties between the catalyst and PEM, and increase the electrode reaction areas, resulted in increasing the performance of the μDMFC.

A Novel Structure of Membrane Electrode Assembly for DMFC

2009 ◽  
Vol 60-61 ◽  
pp. 339-342
Author(s):  
Chun Guang Suo ◽  
Xiao Wei Liu ◽  
Xi Lian Wang
Keyword(s):  
Fuel Cell ◽  
Direct Methanol Fuel Cell ◽  
Catalyst Layer ◽  
Membrane Electrode Assembly ◽  
Gas Diffusion ◽  
Cathode Side ◽  
Membrane Electrode ◽  
Anode Side ◽  
Direct Methanol ◽  
Methanol Fuel Cell

Membrane electrode assembly (MEA) is the key component of direct methanol fuel cell (DMFC), the structure and its preparation methods may bring great effects on the cell performances. Due to the requirement of the high performance of the MEA for the micro direct methanol fuel cell (DMFC), we provide a novel double-catalyst layer MEA using CCM-GDE (Catalyst Coated Membrane，CCM；Gas Diffusion Electrode，GDE) fabrication method. The double-catalyst layer is formed with an inner catalyst layer (in anode side: PtRu black as catalyst, in cathode side: Pt black as catalyst) and an outer catalyst layer (in anode side: PtRu/C as catalyst, in cathode side: Pt/C as catalyst). The fabrication procedures are important to the new structured MEA, thus three kinds of fabrication methods are studied, including CCM-GDE, GDE-Membrane and CCM-GDL methods. It was found that the CCM-GDE technology may enhance the contact properties between the catalyst and PEM, and increase the electrode reaction areas, resulted in increasing the performance of the DMFC.

scholarly journals A Kernel for Calculating PEM Fuel Cell Distribution of Relaxation Times

2021 ◽  
Vol 9 ◽  
Author(s):  
Andrei Kulikovsky
Keyword(s):  
Fuel Cell ◽  
Oxygen Transport ◽  
Relaxation Times ◽  
Catalyst Layer ◽  
Pem Fuel Cell ◽  
Negative Real Part ◽  
Gas Diffusion ◽  
Transport Processes ◽  
Transport Layer ◽  
Cathode Side

Impedance of all oxygen transport processes in PEM fuel cell has negative real part in some frequency domain. A kernel for calculation of distribution of relaxation times (DRT) of a PEM fuel cell is suggested. The kernel is designed for capturing impedance with negative real part and it stems from the equation for impedance of oxygen transport through the gas-diffusion transport layer (doi:10.1149/2.0911509jes). Using recent analytical solution for the cell impedance, it is shown that DRT calculated with the novel K2 kernel correctly captures the GDL transport peak, whereas the classic DRT based on the RC-circuit (Debye) kernel misses this peak. Using K2 kernel, analysis of DRT spectra of a real PEMFC is performed. The leftmost on the frequency scale DRT peak represents oxygen transport in the channel, and the rightmost peak is due to proton transport in the cathode catalyst layer. The second, third, and fourth peaks exhibit oxygen transport in the GDL, faradaic reactions on the cathode side, and oxygen transport in the catalyst layer, respectively.

Study of the Variation of Catalyst Loading in Cathode for SPEEK/CSMM Membrane in Direct Methanol Fuel Cell (DMFC)

2014 ◽  
Vol 69 (9) ◽  
Author(s):  
S. E. Rosli ◽  
M. N. A. Mohd-Norddin ◽  
J. Jaafar ◽  
R. Sudirman
Keyword(s):  
Fuel Cell ◽  
Membrane Electrode Assembly ◽  
Cathode Side ◽  
Catalyst Loading ◽  
Methanol Permeability ◽  
Membrane Electrode ◽  
Anode Catalyst ◽  
Ether Ether Ketone ◽  
Poly Ether Ether Ketone ◽  
Direct Methanol

Variation of anode catalyst loading for modified sulfonated poly (ether ether ketone) (SPEEK) with charged surface modifying macromolecules (cSMM) membrane was studied, in order to get the higher performance in DMFC. The best optimal anode catalyst loading was 4 mgcm-2 for 30% Pt/Ru based on our previous result for this application.  The modified SPEEK/CSMM membrane was characterized to ensure of its better performance in term of water uptake and methanol permeability. In cathode side, the effect of 5% and 10% Pd/C  in 2,4 and 6 mgcm-2 of catalyst loading has been investigated with a fuel cell assembly. The preparation method of catalyst ink and membrane electrode assembly (MEA) was based on Dr. Blade method and hot pressing by using catalyzed diffusion media (CDM) method. The air flowrates were varied from 25-1000ml min-1, while 1M methanol concentrations, 1 ml min-1 of methanol flowrate and 60°C operating temperature were kept constant. These parameters were tested on the performance of single cell DMFC with 4 cm2 electrodes.The optimization catalyst loading will enhance the DMFC performance.  It was found, the best optimal cathode catalyst loading was 4 mgcm-2 for 10% Pd/C with  4 mgcm-2 for 30% Pt/Ru in anode side for this application. 

The Effect of Variable Catalyst Loading in Electrodes on PEM Fuel Cell Performance

2005 ◽  
Author(s):  
R. Roshandel ◽  
B. Farhanieh
Keyword(s):  
Fuel Cell ◽  
Current Density ◽  
Catalyst Layer ◽  
Pem Fuel Cell ◽  
Pem Fuel Cells ◽  
Cell Performance ◽  
Cathode Side ◽  
Catalyst Loading ◽  
Fuel Cell Performance ◽  
Reactant Concentration

Catalyst layers are one the important parts of the PEM fuel cells as they are the main place for electrochemical reaction taking place in anode and cathode of the cells. The amount of catalyst loading of this layer has a large effect on PEM fuel cell performance. Non-uniformity of reactant concentration could lead to a variation of current density in anode and cathode catalyst layer. The main reason for this phenomenon is porosity variation due to two effects: 1. compression of electrode on the solid landing area and 2. Water produced at the cathode side of diffusion layer. In this study the effect of variable current density in anode and cathode electrode on cell performance is investigated. It has shown that better cell performance could be achieved by adding a certain amount of catalyst loading to each electrode, with respect to the reactant concentration.

An efficient and durable novel catalyst support with superior electron-donating properties and fuel diffusivity for a direct methanol fuel cell

2017 ◽  
Vol 7 (21) ◽  
pp. 5079-5091 ◽  
Author(s):  
Arpita Ghosh ◽  
S. Ramaprabhu
Keyword(s):  
Fuel Cell ◽  
Methanol Oxidation ◽  
Direct Methanol Fuel Cell ◽  
Catalyst Support ◽  
Research Topic ◽  
Catalyst Loading ◽  
Anode Side ◽  
Direct Methanol ◽  
Novel Catalyst ◽  
Methanol Fuel Cell

The direct methanol fuel cell (DMFC) is projected as one of the most promising next-generation fuel cell technologies and reducing the catalyst loading at the anode side with an improvement in the sluggishness of methanol oxidation has become the key research topic in the field.

Liquid Water Transport and Distribution in Fibrous Porous Media and Gas Channels

2008 ◽  
Author(s):  
Dirk Rensink ◽  
Jo¨rg Roth ◽  
Stephan Fell
Keyword(s):  
Fuel Cell ◽  
Liquid Water ◽  
Catalyst Layer ◽  
Pem Fuel Cell ◽  
Pem Fuel Cells ◽  
Gas Diffusion ◽  
Operating Conditions ◽  
Cathode Side ◽  
Porous Layers ◽  
Micro Channels

In a polymer electrolyte membrane (PEM) fuel cell water is produced by electrochemical reactions in the catalyst layer on the cathode side. The water diffuses through the catalyst layer and a fibrous substrate into gas channels where it is transported away by convection. The fibrous substrate represents the gas diffusion media (GDM). Sometimes the GDM has a thin microporous layer on the side facing the catalyst layer. The same layer structure can be found on the anode side. All layers together are the porous layers of a PEM fuel cell. Under certain operating conditions condensation can occur in the porous layers which might lead to flooding conditions and — if the liquid water forms droplets which grow together in the gas channels — the complete blockage of the channels. Both situations can lead to a local starvation of reactant gases with negative impact on fuel cell performance and durability. The void space of the hydrophobic fibrous substrate in a PEM fuel cell can be interpreted as micro channels in a broader sense, especially if liquid phase transport from the catalyst layer towards the gas channels is in focus. Due to the small dimensions with effective channel diameter in the range of micrometer the flow of liquid water is governed by capillary forces. The same applies for the gas channels at low gas velocities since the Bond and Capillary numbers are well below one. Thus the investigation of liquid water flow and distribution under low gas velocities in the hydrophobic fibrous substrate and the spreading of liquid water along the hydrophilic gas channel walls under capillary action is of special interest for PEM fuel cells and investigated here.

Effect of Cathode Gasket Thickness to Performance of Direct Methanol Fuel Cells

2008 ◽  
Author(s):  
Hoon Choi ◽  
Yong-Sheen Hwang ◽  
Dae-Young Lee ◽  
Seo Young Kim ◽  
Suk-Won Cha
Keyword(s):  
Direct Methanol Fuel Cells ◽  
Membrane Electrode Assembly ◽  
Gas Diffusion ◽  
Differential Pressure ◽  
Cathode Side ◽  
Membrane Electrode ◽  
Ohmic Loss ◽  
Performance Effect ◽  
Direct Methanol ◽  
Made In

This study considers the performance effect about a variation of the gasket thickness at the cathode side of the DMFC’s (Direct Methanol Fuel Cell) stack. Stack performance is largely influenced by the compressed thickness of GDL (Gas Diffusion Layer). The compressed thickness of GDL is directly controlled by gasket thickness. When GDL is not compressed enough, the ohmic loss is increased. Additionally, the differential pressure is decreased, because the channel of the separator is not blocked by GDL. On the contrary, being compressed extremely, GDL or MEA (Membrane Electrode Assembly) is physically damaged. The differential pressure is increased as well. In this respect, the optimization of the gasket thickness is one of the important factors to maximize the stack performance. In this study, the unit cell stacks with respect to changing gasket thickness at the cathode side are made in order to verify the effect about the compressed thickness of GDL. It is shown how the optimal gasket thickness may be achieved at the cathode side.

Effect of gradient porosity and catalyst loading on the performance of direct methanol fuel cell with ordered electrode

2021 ◽  
pp. 1-24
Author(s):  
Jinghui Jiang ◽  
Xianda Sun
Keyword(s):  
Direct Methanol Fuel Cells ◽  
Transport Model ◽  
Knudsen Diffusion ◽  
Catalyst Layer ◽  
Catalyst Loading ◽  
Two Phase ◽  
Effective Strategies ◽  
Direct Methanol ◽  
Mass Transport Model ◽  
Catalyst Utilization

Abstract Constructing the ordered catalyst layer is one of the most effective strategies to maximize the catalyst utilization in direct methanol fuel cells. To gain insight into the mass and charge transports in ordered catalyst layer, herein, a 2D two-phase mass-transport model involving Knudsen diffusion was proposed. It is found that the simulation results of the model with Knudsen diffusion are more consistent with the experimental results than that of the model without Knudsen diffusion. It has been demonstrated that higher porosity near the oxygen diffusion layer facilitates the oxygen transport, and the optimal porosity is obtained by balancing mass and charge transport resistances in the ordered catalyst layer. In contrast, higher catalyst loading near membrane improves the cell performance significantly. The highest peak power density of 56.5 mW cm-2 is achieved, when the catalyst loading of the outer and inner layer is 0.15 mg cm-2 and 0.85 mg cm-2, respectively.

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