Highly Ordered Nanoporous Carbon Scaffold with Controllable Wettability as the Microporous Layer for Fuel Cells

Abstract

We introduce a novel self-standing, nanoporous carbon scaffold (NCS, 25 μm thick), with an ordered inverse opal pore structure (∼85 nm pore) as a microporous layer (MPL) in a polymer electrolyte membrane fuel cell. Unlike previous studies, through chemical functionalization of the pore surfaces, the wettability of the MPL is controllably modified without altering the pore structure. Ex situ environmental scanning electron microscopy experiments revealed water sorption in the hydrophilic NCS under moderate relative humidity (RH) conditions but not in the hydrophobic NCS, wherein water condensation on the surface was noted only at high RH. The influence of structure and wettability of different MPLs on cell performance was gleaned from steadystate cell polarization behavior. For cells operated under dry conditions (≤80% RH), the limiting current for cells with a hydrophilic NCS MPL was the highest while that for cells with a hydrophobic NCS MPL was the lowest regardless of the level of water saturation (RH).

Scalable nanoporous carbon films allow line-of-sight 3D atomic layer deposition of Pt: towards a new generation catalyst layer for PEM fuel cells

“…As explained in our recent work, [8][9][10] the NCS is fabricated by a combination of sonication and low energy ball-milling of mixtures of mesophase pitch (MP)/n-butanol (BtOH), polyvinyl alcohol (PVA)/water and silica nanoparticles/1,3-propanediol (PD)/water (Fig. 1 and Fig.…”

“…To date, we have reported on NCS membranes with pore sizes of either 22 or 85 nm in two different applications. In one of these studies, 9 the internal surface NCS85 was modified to control its wettability, revealing that a combination of small hydrophobic pores and larger hydrophilic cracks facilitate oxygen and water transport, respectively. In our other work, 10 NCS22 and NCS85 were used as a model of an ideal nanoporous material to study the dynamics of nanoliter droplet imbibition and capillary rise for application in natural porous media, e.g., shale rocks.…”

Study of substrate‐free microporous layer of proton exchange membrane fuel cells

“…17,18 Thus, a dry technique is proposed to prepare MPL for PEMFCs with convenient operation, solvent-free and excellent reproducibility. 19,20 Researchers have endeavored to enhance fuel cells' performance in terms of fabricating new materials, 3,[21][22][23][24] constructing favorable structures 17,[25][26][27][28] and optimizing components of GDL. [29][30][31] From the material aspect, some studies have demonstrated the use of carbon fiber (CF), carbon nanotube and graphene in MPL to improve the electrical performance and gas permeability of PEMFCs.…”

Electrochemistry of new generation conformal polyaniline/carbon scaffolds with monodispersed nanopores and high capacitance

“…11–13 Largely for these reasons, we have developed a self-supported nanoporous carbon scaffold (NCS), which has shown significant promise in many applications. 14–17 The NCS, with its fully controllable, monodispersed, and 3-D interconnected nanopore size (ranging from 5 to 100 nm in diameter) and thickness (1 to 1000 μm), has been shown to be very useful as a novel Pt catalyst support, 14 as a microporous layer in PEM fuel cells, 15 and as a model structure for the investigation of liquid imbibition into nanoporous media. 16 The unique structure of the NCSs greatly facilitates the use of the material in practice both in flow-by and flow-through modes, thus generating higher mass transport rates (equating to higher currents) and allowing full utilization of the internal surface.…”