Direct Dimethyl Ether Fuel Cell with Much Improved Performance

Abstract

Due to several apparent advantages over methanol, dimethyl ether (DME) has been viewed as a promising alternative fuel for direct fuel cell technology. Similar to methanol, DME oxidation requires a surface oxidant, such as OH, for the removal of adsorbed CO. Consequently, the reaction occurs at much faster rates on binary PtRu catalysts than Pt alone. In this work, PtRu catalysts with a wide variety of Pt-to-Ru ratios were systematically studied in the direct DME fuel cell (DDMEFC) operating at 80°C. A Pt 50 Ru 50 catalyst was found to perform the best at high and middle voltages, while a Pt 80 Ru 20 catalyst performed best at low voltages. DDMEFC operation conditions, such as DME flow rate, anode back pressure, DME-to-water molar ratio, and membrane thickness, were also studied in order to maximize the cell performance. A maximum power density of 0.12 W cm −2 obtained in this work exceeds the highest reported DME performance.In comparison with the direct methanol fuel cell (DMFC), the optimized DDMEFC performs better at cell voltages higher than 0.55 and 0.49 V with feed concentrations of methanol of 0.5 and 1.0 M, respectively.

Electrochemical Characterization of Low-Temperature Direct Ethanol Fuel Cells using Direct and Alternate Current Methods

“…Low-temperature polymer electrolyte membrane fuel cells (PEM FCs) are considered promising energy sources for sustainable and environment-friendly energy conversion [1]. Among various PEMs, direct methanol (DMEFCs), formic acid (DFAFCs), dimethyl ether (DDMEFC), and ethanol fuel cells (DEFCs) have many potential advantages, such as high theoretical energy density of the fuel, high theoretical thermodynamic efficiency of fuel oxidation, and ease of storage and transportation, and in case of ethanol, the ease of production and carbon-neutrality [2][3][4][5][6][7].…”

High‐Activity PtRuPd/C Catalyst for Direct Dimethyl Ether Fuel Cells

“…70 mV lower than on Pt 50 Ru 50 /C (0.36 V vs. 0.43 V). The observed broad oxidation peak on the Pt 46 Ru 44 Pd 10 /C catalyst is attributed to the oxidation of CO ad and (‐CHO) ad 3. In contrast, no significant DME oxidation peak is observed on Pt 50 Ru 50 /C at room temperature.…”

“…In this work, a carbon‐supported Pt 46 Ru 44 Pd 10 catalyst for DME electrooxidation was rationally designed under the guidance of density functional theory (DFT) calculations. The Pt‐to‐Ru ratio was kept at 1:1 as Pt 50 Ru 50 showed the better performance in the kinetic region of DDMEFC than other Pt‐to‐Ru ratios in our previous study 3. 11 The activity of the new ternary catalyst toward DME oxidation in an electrochemical cell and in a fuel cell was demonstrated to be superior to that of a commercial Pt 50 Ru 50 /C reference catalyst (HiSPEC 12100, Johnson Matthey).…”

“…Dimethyl ether (DME), a less toxic fuel than methanol, has been investigated in the last decade as a possible alternative fuel for the direct‐feed fuel cells 2. The theoretical open cell voltage (OCV) of the direct DME fuel cell (DDMEFC) is comparable to that of the DMFC (1.18 V vs. 1.21 V) 3. Upon oxidation to CO 2 , a DME molecule releases 12 electrons, resulting in a higher energy density of DME than that of methanol (8.2 vs. 6.1 kWh kg −1 ) 4.…”

“…To date, PtRu has been recognized as the state‐of‐the‐art for the DDMEFC anode 8. However, DME oxidation at PtRu remains kinetically impaired relative to that of methanol 3. According to the mechanism proposed for DME oxidation on Pt,5a, 9 a high activation barrier for the CO bond cleavage may be responsible for the slow kinetics of DME oxidation compared to that of methanol, as oxidation of chemisorbed species on Pt, such as CO ads , is the same as that accepted for methanol oxidation.…”