Lale Işıkel Şanlı

Electrosprayed catalyst layers based on graphene–carbon black hybrids for the next-generation fuel cell electrodes

Here, we report a novel electrode structure with graphene and graphene–carbon black hybrids by electrospraying for polymer electrolyte membrane fuel cells. After syntheses of platinum (Pt)/partially reduced graphene oxide (rGO) and Pt/r-GO/carbon black (CB) hybrid electrocatalysts, suspensions of synthesized electrocatalyst inks were prepared with Nafion® ionomer and poly(vinylidene fluoride-co-hexafluoropropylene) and electrosprayed over carbon paper to form electrodes. Electrosprayed catalyst layer exhibited uniform and small size Pt distribution. As the graphene content increases micrometer-sized droplet, pore formation and surface roughness of the electrode increase. Thus, an open porous electrode structure which is favorable for mass transport is achieved by electrospraying. The maximum power densities, 324 mW cm−2 for Pt/rGO and 441 mW cm−2 for Pt/rGO/CB electrosprayed electrodes, were achieved at a relatively low catalyst loading.

Flexible carbon–cellulose fiber-based composite gas diffusion layer for polymer electrolyte membrane fuel cells

In this study, wet-laying process, mostly used in pulp and paper industry, was employed for the fabrication of composite gas diffusion layers (GDLs) for polymer electrolyte membrane (PEM) fuel cells. Cellulose fiber-based composite GDL was manufactured without using polluting, volatile organic compounds so that a green and environmentally friendly process was utilized. Fabricated cellulose-based composite GDLs were characterized ex situ by resistivity, mechanical strength, and porosity measurements and investigation of their morphology by SEM. Carbon–cellulose fiber-based electrically conducting composite GDLs with excellent flexibility, uniformity, and porosity were achieved. Gas diffusion electrodes were prepared using electrospraying technique to provide high surface area and homogenous dispersion. Moreover, PEM fuel cell performance of the fabricated composite GDLs was investigated for the first time in literature.

Macroscopic assembly of flexible and strong green graphene fibres

Graphene fibres have great potential in future wearable electronics due to their promising thermal and electrical properties. However, fibre brittleness limits their implementation and researchers are still seeking easily scalable and eco-friendly production methods. Here we propose a green and continuous wet-spinning assembly approach to continuously spin flexible graphene oxide (GO) fibres. Highly stable aqueous GO suspensions up to 40 mg mL−1 are achieved and GO fibres are spun from highly oriented liquid crystals through a customized continuous fibre production line. As-spun GO fibres with specific ultimate tensile strength of 7 N/tex show strain to failure (%) of 10%; subsequent NaBH4 chemical reduction gives graphene fibres with electrical conductivity of 214 S cm−1. The scalable production presented here facilitates flexible, strong and electrically conductive graphene fibres, which have emerged as promising graphene based electronic textiles and sensors.

Correction to: Electrosprayed catalyst layers based on graphene–carbon black hybrids for the next-generation fuel cell electrodes

The article “Electrosprayed catalyst layers based on graphene–carbon black hybrids for the next-generation fuel cell electrodes,” written by Lale Işıkel Şanlı, Begüm Yarar, Vildan Bayram, and Selmiye Alkan Gürsel, was originally published electronically on the publisher’s internet portal (currently SpringerLink) on October 25, 2016, without open access.

Design and Modeling of High Temperature Water Free Proton Exchange Membranes in DEA PEMFC Operations

Polymer electrolyte membrane fuel cell (PEMFC) is a greatalternative in transportation however there are still some issues onthe application of PEMFC, such as complexity in balance-of-plantdesign and cost of the system. Dead ended anode (sealed offanode) design might be a solution to reduce the complexity ofPEMFC. DEA operation eliminates the expensive hardware, suchas mass flow controllers, hydrogen recovery system andhumidifiers of PEMFC system. Moreover, the DEA operation ofNafion® is experiencing the disadvantages of low operationtemperature (40-80 °C) as the corrosion of the expensiveelectrodes by accumulated water. Beyond it is low operationtemperatures; Nafion® is also expensive and increases the cost ofthe PEMFC. Hence, in this study, the water free, high temperatureand cost competitive radiation induced grafted membranes weresynthesized and tested in both flow through anode (FTA) and deadended anode (DEA) operation in PEMFC.