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The study has prepared highly conducting polymer electrolyte films using solution cast technique with poly(vinylidene fluoride‐co‐hexafluoropropylene) PVDF‐HFP, mixture of ethylene carbonate (EC), and propylene carbonate (PC) as plasticizer and latex of Calotropis gigantea (CGL) as an ionic source. In this study, four films are prepared using PVDF‐HFP:CGL in ratio 1:1 with the increasing concentration of EC+PC as 1, 2, 3, and 4 M named as 1:1:1, 1:1:2, 1:1:3, 1:1:4. The prepared polymer electrolyte is examined by polarized optical microscopy (POM), elemental dispersive X‐ray technique (EDX), and complex impedance spectroscopy. EDX and POM are studied for the surface morphology of all prepared samples and to investigate the porous nature of films. The enhancement in ionic conductivity occurs due to CGL and increasing amount of EC‐PC. Conductivity of highest composition (1:1:4) polymer electrolyte film is found to be ≈10−3 S cm−1. The optimized polymer electrolyte film is considered as a promising candidate for application in supercapacitors. [ABSTRACT FROM AUTHOR]

This paper reports on the quantitative assessment of the oxygen reduction reaction (ORR) electrocatalytic activity of electrodeposited Mn/polypyrrole (PPy) nanocomposites for alkaline aqueous solutions, based on the Rotating Disk Electrode (RDE) method and accompanied by structural characterizations relevant to the establishment of structure-function relationships. The characterization of Mn/PPy films is addressed to the following: (i) morphology, as assessed by Field-Emission Scanning Electron Microscopy (FE-SEM) and Atomic Force Microscope (AFM); (ii) local electrical conductivity, as measured by Scanning Probe Microscopy (SPM); and (iii) molecular structure, accessed by Raman Spectroscopy; these data provide the background against which the electrocatalytic activity can be rationalised. For comparison, the properties of Mn/PPy are gauged against those of graphite, PPy, and polycrystalline-Pt (poly-Pt). Due to the literature lack of accepted protocols for precise catalytic activity measurement at poly-Pt electrode in alkaline solution using the RDE methodology, we have also worked on the obtainment of an intralaboratory benchmark by evidencing some of the time-consuming parameters which drastically affect the reliability and repeatability of the measurement. [ABSTRACT FROM AUTHOR]

Electrodeposition and ageing under oxygen reduction reaction (ORR) of Mn-X/PPy (X=Co, Mg, Ni; PPy=polypyrrole) and Mn-Ag/G (G=graphene) composite electrocatalysts have been studied by quasi-in-situ soft X-ray absorption and fluorescence microspectroscopy. The fabricated materials exhibit micro-grained morphologies in which Mn is present mainly as Mn2+, accompanied by combinations of Co0/Co2+ and Ni0/Ni2+. Ageing leads to the formation of progressively larger mesoscopic aggregates. Initial ageing yields more active Mn3+ and Mn4+, in agreement with an improved ORR behaviour. Prolonged ageing causes the loss of Mn3+ and Mn4+ from the surface, in correlation with a degradation of the ORR response. In the investigated ageing period, Mn-Mg/PPy exhibits the best durability, with about half of the catalyst grains still showing the presence of Mn3+/Mn4+, while the others consist mainly of Mn2+. In Mn-Ni/PPy, the Ni2+ content tends to increase with ageing whereas Co3+ forms in the Mn-Co/PPy composites. [ABSTRACT FROM AUTHOR]

In this paper, we report on the use of high-space resolution soft X-ray fluorescence microspectroscopy for the study of electrodeposited composites containing catalytic ternary metal nanostructures. X-ray fluorescence maps are interpreted in terms of a dynamic mathematical model of the electrode morphology and metal space distribution, allowing to reproduce the observed space patterns and electrochemical transients by assigning an appropriate set of electrokinetic parameters. The discussed materials-science case is the electrochemical growth of a Mn-Mg-Cu-polypyrrole nanocomposite electrocatalyst material - free of expensive Pt and environmentally unfriendly Co - with promising performance for fuel-cell oxygen electrodes. The synergy of high-resolution compositional mapping with electrokinetic modelling not only provides the general rationale for quantitative use of potentially large compositional distribution datasets but also yields unprecedented insight into the specific catalyst synthesis process. The expounded application is just a prototypical case study of a more general approach, which can be employed for the understanding of electrochemical material science processes, both in situ and ex situ, as well as for the characterisation of the corresponding products, with no other limitations in principle than X-ray transmission and beam damage. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]