Proton-exchange membrane fuel cells (PEMFCs) have received great attention as a potential alternative energy device for internal combustion engines due to their high conversion efficiency compared to other fuel cells. The main hindrance for the wide commercial adoption of PEMFCs is the high cost, low proton conductivity, and high fuel permeability of the state-of-the-art Nafion membrane. Typically, to improve the Nafion membrane, a wide range of strategies have been developed, in which efforts on the incorporation of carbon nanomaterial (CN)-based fillers are highly imperative. Even though many research endeavors have been achieved in relation to CN-based fillers applicable for Nafion, still their collective summary has rarely been reported. This review aims to outline the mechanisms involved in proton conduction in proton-exchange membranes (PEMs) and the significant requirements of PEMs for PEMFCs. This review also emphasizes the improvements achieved in the proton conductivity, fuel barrier properties, and PEMFC performance of Nafion membranes by incorporating carbon nanotubes, graphene oxide, and fullerene as additives.

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Potential carbon nanomaterials as additives for state-of-the-art Nafion electrolyte in proton-exchange membrane fuel cells: a concise review

Nafion membranes are still the dominating material used in the polymer electrolyte membrane (PEM) technologies. They are widely used in several applications thanks to their excellent properties: high proton conductivity and high chemical stability in both oxidation and reduction environment. However, they have several technical challenges: reactants permeability, which results in reduced performance, dependence on water content to perform preventing the operation at higher temperatures or low humidity levels, and chemical degradation. This paper reviews novel composite membranes that have been developed for PEM applications, including direct methanol fuel cells (DMFCs), hydrogen PEM fuel cells (PEMFCs), and water electrolysers (PEMWEs), aiming at overcoming the drawbacks of the commercial Nafion membranes. It provides a broad overview of the Nafion-based membranes, with organic and inorganic fillers, and non-fluorinated membranes available in the literature for which various main properties (proton conductivity, crossover, maximum power density, and thermal stability) are reported. The studies on composite membranes demonstrate that they are suitable for PEM applications and can potentially compete with Nafion membranes in terms of performance and lifetime.

Composite Polymers Development and Application for Polymer Electrolyte Membrane Technologies—A Review

Recent developments in graphene based novel structures for efficient and durable fuel cells

Fuel cells are among the promising sources of clean energy, considering the low costs, low acoustical pollution, and the high-energy conversion. The remarkable features of graphene and its derivatives have triggered research studies on their applications in PEMFCs. PEMFCs still face some operational challenges for large-scale applications, including high costs, low proton conductivities at high temperatures, mechanical/thermal stabilities, and high fuel crossover. The unique characteristics of graphene-based materials, i.e., high electrochemical stability, good mechanical strength, large surface area, and excellent thermal stability, have been exploited in PEMFCs. This review discusses the potential role of graphene and graphene oxide (GO) in the membranes’ structural modifications, and utilization of polymer matrices such as SPEEK, PBI, PANI, SPAES, Nafion, and PVA polymers. The synthesis/functionalization of GO has been investigated with novel composite membranes and mechanisms involved in the enhancements of proton conductions, water uptakes, IECs, and power densities. Graphene materials showed excellent dispersion in solvents and alteration of membrane morphologies. The preceding properties are attributed to the formation of oxygen-based functional groups in GO nano-layers. The incorporation of graphene in other fuel cells, i.e., direct methanol fuel cells and biofuel cells, has exhibited commendable performance and appeared promising for commercial applications, especially with the reduction of fuel crossover. 

Recent developments in graphene and graphene oxide materials for polymer electrolyte membrane fuel cells applications

Despite being generated from the same element and having some of the properties commonly shared, each type of carbon allotrope possessing divergent shape confers unique and distinguishable physicochemical properties, thereby making them attractive for a wide range of potential applications. Moreover, research progress has allowed for further tailoring the properties in a controlled way to design more fascinating and aesthetically pleasing architectures with outstanding materials properties. In fact, some chemically modified carbon allotropes and their products have shown significant promise to solve a number of major issues in polymer exchange membrane fuel cells (PEMFCs) and supercapacitors (SCs) such as efficient low Pt loaded oxygen reduction reaction (ORR) catalysts, carbon allotrope-based proton conductors for PEMFC electrolyte, carbon monoxide (CO) tolerant anode catalysts for PEMFC, and carbon allotropes-based SC electrodes. The tremendous progress made in carbon-based materials facilitates those technologies more realistically towards large-scale implementation in terms of increasing the stack power density and reducing cost. In this view, this review will provide a thorough insight for researchers into the use of carbon allotropes and relevant products for PEMFCs and SCs. Carbon allotropes including fullerene, CNT and graphene possess divergent shapes confering unique and distinguishable physicochemical properties. Moreover, research progress has allowed for further tailoring the properties in a controlled way to design more fascinating and aesthetically pleasing architectures with outstanding materials properties suitable for some key components in fuel cells and supercapacitors. 

Energy Conversion and Storage in Fuel Cells and Super-Capacitors from Chemical Modifications of Carbon Allotropes: State-of-Art and Prospect

https://research.birmingham.ac.uk/portal/files/70637462/Ibrahim_et_al_GO_nafion_composite_membrane_International_Journal_of_Hydrogen_Energy_2019.pdf

Oheen Hossain

Papers

GO-nafion composite membrane development for enabling intermediate temperature operation of polymer electrolyte fuel cell