The parameter space for scalable integration of atomically thin graphene with Nafion for proton exchange membrane (PEM) applications

Abstract

Incorporating atomically thin graphene into proton exchange membranes (PEMs) via scalable and facile processes presents the potential for advancing energy conversion and storage applications while mitigating persistent issues of undesired species crossover.

Ultra-thin proton conducting carrier layers for scalable integration of atomically thin 2D materials with proton exchange polymers for next-generation PEMs

“…Graphene is synthesized via low pressure chemical vapor deposition (CVD) in a custom-built, 1′′ diameter tube furnace reactor. 7,11,15–21,23,29,32 In brief, Cu foil (HA, 18 μm thickness, JX Holdings) is cleaned via sonication in ∼20% Nitric Acid followed by DI water wash and air drying. 11 The Cu foil is heated to ∼1060 °C and annealed under 100 sccm H 2 for 45 minutes, then 300 sccm for an additional 15 minutes.…”

“…Hot press: graphene on Cu foil is pressed to Nafion by sandwiching it between two sheets of PTFE-coated fiberglass sheets (McMaster Carr, ∼10 mil thickness) at ∼140 °C under 1000 psi for 3 minutes. 7,11,29 Cold press: a thin layer of Nafion (1 wt% Nafion solution, 1100 EW – equivalent weight of Nafion in alcohol, Ion Power) is casted ( via drop-casting or spin-coating) on CVD graphene on Cu before pressing N211 via sandwiching between the PTFE-coated fiberglass sheets at room temperature under 1000 psi for 3 minutes. Spin + scoop: Graphene on Cu foil is coated with a thin Nafion film via spin-coating.…”

“…Proton transport characterization of the fabricated membranes were performed by supplying H 2 gas as the source of protons and by adding ∼0.25-inch diameter platinum-carbon electrodes (Pt/C, 0.2 mg cm −2 Pt loading, Fuel cell store, ∼0.32 cm 2 ) via hot press at ∼200 psi and ∼140 °C for ∼1 minute. 7,11,29 Before testing, the membranes were soaked in DI water for 10 minutes to ensure the Nafion was fully hydrated (as prepared). Membranes were loaded into a custom-built miniature fuel cell and ∼40 sccm of humidified H 2 gas (99.9999%, AL Gas) is introduced to both sides of the membrane (see Fig.…”

“…Nafion directly onto CVD graphene grown on Cu foil, has been explored in prior studies and optimized to enable large area graphene transfer for applications in fuel cell, redox flow batteries, isotope separations and beyond. 2,7,11,29 However, oxidation of the Cu underneath defects in graphene can cause damage to graphene compromising selectivity, necessitating new approaches. 29…”

“…2,7,11,29 However, oxidation of the Cu underneath defects in graphene can cause damage to graphene compromising selectivity, necessitating new approaches. 29…”