Grooved electrodes for high-power-density fuel cells

Abstract

Proton exchange membrane fuel cells (PEMFCs) are leading candidates to decarbonize the transport sector, but widespread deployment will require improvements in lifetime, fuel economy and cost. Here we present the grooved electrode, an alternative electrode structure that enhances PEMFC performance and durability by coupling high ionomer (ion-conducting binder) content for improved H+ transport with grooves for rapid O2 transport. Grooved electrodes provide up to 50% higher performance than state-of-the-art conventional electrodes under standard operating conditions. Fuel cell diagnostics combined with multiphysics modelling demonstrate that grooved electrodes provide facile O2 transport despite their high ionomer content, enabling improved reaction rate uniformity. Grooved electrodes also provide improved durability, with less performance loss after carbon corrosion compared with baseline electrodes. Machine learning analysis demonstrates the potential to further optimize grooved structures for next-generation PEMFCs with enhanced performance and durability, enabling smaller and cheaper fuel cell stacks with higher fuel efficiency.

It's time for an update—A perspective on fuel cell electrodes

“…A recent study demonstrated up to 50% increase in performance using commercial materials, just by rearranging how the materials were positioned. [8] In this perspective, we discuss whether advancements in the electrode structure are the breakthrough we need to get PEMFCs to the market.…”

“…2. Grooved electrodes reported by Lee et al [8] feature electrode ridges with higher ionomer content relative to conventional electrodes and grooves that separate the ridges. The high ionomer content promotes rapid proton transport even under dry operating conditions, but the higher ionomer content comes with the price of larger oxygen transport resistance associated with smaller electrode pores and thicker ionomer films.…”

A High-Performance Membrane Electrode Assembly with an Ultrathin Proton Exchange Membrane Based on a Wet-Combining Interface Forming Strategy

“…Due to their high efficiency, low pollution, and low operating temperature, proton exchange membrane fuel cells (PEMFCs) are regarded as a promising technology route to facilitate the construction of a low-carbon world. − A typical PEMFC is comprised of membrane electrode assemblies (MEAs), bipolar plates, sealing parts, and end plates. , The MEAs are the sites of electrochemical reactions, in which the chemical energy of the hydrogen fuel is converted into electrical energy. The components of an MEA mainly include a proton exchange membrane (PEM), catalyst layers (CLs), microporous layers (MPLs), and gas diffusion layers (GDLs).…”

Proton Transport Functionality-Enabled Carbon Support for Improved Fuel Cell Performance and Durability

“…Design of cathode electrodes with superior oxygen reduction reaction (ORR) kinetics and transport properties remains a major challenge toward commercialization of proton exchange membrane (PEM) fuel cells. − The perfluorosulfonic acid (PFSA) ionomer used in the fuel cell electrodes acts both as a binder and a proton conduction agent within the cathode catalyst layer (CCL). The PFSA ionomer comprises of fluorocarbons that are environmentally unfriendly and also poison the carbon-supported platinum-alloy ORR electrocatalysts via adsorption of the sulfonate groups in their side chains. , Carbon supports with accessible mesopores have enabled improvement in ORR activity via spatial separation of Pt and ionomer, and newer grooved electrode designs have enabled a high-current density performance with preferential pathways for rapid O 2 mass transport. ,− However, these electrodes still require significant ionomer content for proton transport. It is critical to design new materials where the electrodes utilize only a minimal amount of ionomer required for binding, thereby enabling higher ORR activity without compromising the proton transport properties.…”