Efficient Chitosan/Nitrogen-Doped Reduced Graphene Oxide Composite Membranes for Direct Alkaline Ethanol Fuel Cells.

Selestina Gorgieva,Azra Osmić,Boštjan Genorio,Sigrid Wolf,Mojca Božič,Silvo Hribernik,Jurij Svete,Viktor Hacker

doi:10.3390/ijms22041740

Abstract

Herein, we prepared a series of nanocomposite membranes based on chitosan (CS) and three compositionally and structurally different N-doped graphene derivatives. Two-dimensional (2D) and quasi 1D N-doped reduced graphene oxides (N-rGO) and nanoribbons (N-rGONRs), as well as 3D porous N-doped graphitic polyenaminone particles (N-pEAO), were synthesized and characterized fully to confirm their graphitic structure, morphology, and nitrogen (pyridinic, pyrrolic, and quaternary or graphitic) group contents. The largest (0.07%) loading of N-doped graphene derivatives impacted the morphology of the CS membrane significantly, reducing the crystallinity, tensile properties, and the KOH uptake, and increasing (by almost 10-fold) the ethanol permeability. Within direct alkaline ethanol test cells, it was found that CS/N rGONRs (0.07 %) membrane (Pmax. = 3.7 mWcm−2) outperformed the pristine CS membrane significantly (Pmax. = 2.2 mWcm−2), suggesting the potential of the newly proposed membranes for application in direct ethanol fuel cells.

Highlights

The use of environmentally friendly materials to circumvent the steady depletion of fossil fuels, the reduction of global pollution, and electricity consumption, are among the most investigated topics of scientific and technological research in recent decades [1]; all of the above is covered in energy conversion devices, i.e., fuel cells
Critical attention has focused increasingly on direct alkaline ethanol fuel cells (DAEFC), where non-noble metal catalysts can be used, together with widely available ethanol, a fuel produced from biomass feedstocks
Use of anion exchange membranes as ion-conducting polyelectrolytes within fuel cells is a promising, cost-effective approach, where research is focused on their stability, permeability, conductivity, and ultimate cell performance

Summary

Introduction

The use of environmentally friendly materials to circumvent the steady depletion of fossil fuels, the reduction of global pollution, and electricity consumption, are among the most investigated topics of scientific and technological research in recent decades [1]; all of the above is covered in energy conversion devices, i.e., fuel cells. Benign, and environmentally friendly devices, fuel cells have been identified as promising and potent technologies for zero emission, electrochemical energy conversion, and power generation, which, apart from their considerable maturation over the last decade, are still constrained by technological barriers, such as insufficient durability and cell life, as well as the high cost of fuel cell components that hamper their commercialization. For this reason, critical attention has focused increasingly on direct alkaline ethanol fuel cells (DAEFC), where non-noble metal catalysts can be used, together with widely available ethanol, a fuel produced from biomass feedstocks. Since the mobility of hydroxide is only about 57% of the mobility of a proton, a high ion exchange capacity (IEC) is required to achieve high ion conductivity compared to proton exchange membranes (PEMs) [3]

Methods

Results

Conclusion