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European Union identified the battery value chain as strategic for achieving a sustainable and decarbonized economy. Focusing on the environmental sustainability of batteries, this paper presents an application of the Life Cycle Assessment methodology to three flow-redox cells characterized by electrodes made by different materials. The results are referred to one kWh of energy supplied by the cell during its useful life and are calculated following a “from cradle to grave” approach. Negligible differences (lower than 1.5%) are observed in the energy and environmental impacts of the three types of cells, mainly due to the type of electrode and the use phase. A dominance analysis shows that the cell manufacturing (including the raw materials supply) is responsible of more than 58% of most of the impact categories examined

7 Figures, 2 Tables.-- This article also appears in: Giornate dell’Elettrochimica Italiana (GEI 2019)., Transition‐metal‐based materials are among the most active and durable catalysts for the effective electrocatalysis of oxygen‐related reactions. Herein, we present a study on bifunctional catalysts as air electrodes aimed at metal‐air batteries based on nickel and cobalt spinel (NiCo2O4) supported on electrospun carbon nanofibers. The physicochemical features of these transition‐metal‐based catalysts are essential for the understanding of their electrochemical activity. Results show that the major presence of oxidized Ni and Co species (Ni3+ and Co3+) produces higher activity for the oxygen evolution reaction (OER), whereas lower oxidation states of the metals (Ni2+, Co2+, Ni0 and Co0) together with the presence of N‐doped carbon lead to enhanced oxygen reduction reaction (ORR) performance. This study highlights the importance of designing catalysts in terms of crystallographic structure and proper oxidation states of the elements for maximizing their performance., The research leading to these results has received funding from the “Accordo di Programma CNR‐MiSE, Gruppo tematico Sistema Elettrico Nazionale e Progetto: Sistemi elettrochimici per l′accumulo di energia”.

Test di caratterizzazione elettrochimica su membrane Solvay per applicazione in batteria redox a flusso di vanadio

Electrodes based on electrospun nickel carbon nanofibers (Ni/CNF) are investigated as highly active both for anodic and cathodic reaction. Scanning electron microscopy (SEM) aswell as transmission electron microscopy (TEM) analyses showmetal nanoparticles embedded in graphitic carbon nanofibers. A high surface area due to large mesoporous structure formation is calculated for the Ni/CNF by BET analysis. Cyclic voltammetry (CV) results indicate the higher electrocatalytic activity toward the [VO](2+)/[VO2](+) as well as V2+/V3+ redox reactions for Ni/CNF with respect to the bare CNF. Charge-discharge tests show energy efficiency (EE) value of 68%, voltage efficiency (VE) of 72% and a coulomb efficiency (CE) of 94% for Ni/CNF at 160 mA center dot cm(-2). The electrochemical performance recorded at high current density could be ascribed to the high electrical conductivity as well as the polarity on the carbon surface due to the nickel nanoparticles. In particular, an increment in terms of wettability improves the accessibility to the aliphatic and carboxyl groups on the composite surface sample enhancing the reversibility at the electrode/electrolyte interface. (c) 2018 The Electrochemical Society.

Bifunctional materials able to catalyze both the oxygen reduction (ORR) and the oxygen evolution (OER) reactions in alkaline media are still a challenge for the progress of energy conversion and storage devices such as metal-air batteries or unitized regenerative fuel cells. In this work, carbon nanofibers synthesized by electrospinning are modified with a combination of cobalt oxide and metallic cobalt (CoO-Co/CNF) and studied as a bifunctional air electrode for metal-air batteries. The performance of CoO-Co/CNF for both reactions is compared with state-of-the-art catalysts such as Pt/C and IrO 2 . The combination of cobalt oxide and metallic cobalt, finely distributed on the surface of graphitic carbon nanofibers, leads to a bifunctional catalyst with a half-wave potential for the ORR slightly better than Pt/C and a reversibility (ΔE OER-ORR ) of 809 mV. The stability of CoO-Co/CNF is assessed by means of different stress tests: polarizations at high electrochemical potentials (2 V vs. RHE), rapid charge-discharge cycles at ±80 mA cm −2 and long durability tests by charging for 12 h at 60 mA cm −2 and discharging for 8 h at −80 mA cm −2 . CoO-Co/CNF shows a remarkable stability, maintaining, at least, an 82% of its performance for the ORR after the stress tests, even when cycled for more than 100 h.

Il presente documento racchiude la sintesi delle attività sperimentali condotte all'interno della I semestralità di progetto 2019 - "Sistemi di accumulo, compresi elettrochimico e power to gas, e relative interfacce con le reti". L'attività è stata rivolta alla sintesi di materiali e componenti per le diverse tecnologie di accumulo in studio e preliminari studi LCA finalizzati alla valutazione degli impatti in funzione delle scelte tecnologie attuate.

La presente relazione tecnica costituisce il documento consuntivo relativo all'attività scientifica del I anno del PT 2019-21, svolta dagli Istituti di ricerca CNR ITAE ed ICCOM coinvolti nel progetto "Sistemi di accumulo, compresi elettrochimico e power to gas, e relative interfacce con le reti", svolta all'interno del PTR 2019-21 (Gennaio 2019-Dicembre 2019). Le attività sono relative allo sviluppo di materiali e componentistica, fino alla loro ingegnerizzazione, di dispositivi di accumulo avanzati e all'identificazione di processi di accumulo innovativi. L'attività scientifica coordinata dal CNR ITAE si articola in n°4 pacchi di lavoro o WP, così denominati: WP1-Accumulo Elettrochimico, WP2-Accumulo Termico, WP3-Power to Gas e WP4-Aspetti Ambientali. Ogni WP si sviluppa attraverso definite linee di attività (LA), descrittive della specifica tematica che verrà svolta durante la singola annualità. L'obiettivo generale del progetto è rivolto al miglioramento della qualità del servizio di fornitura dell'energia elettrica, attraverso il miglioramento delle tecnologie di accumulo elettrochimico (WP1), termico (WP2) e power to gas (WP3) puntando all'ottimizzazione dei materiali e componenti delle specifica tecnologia investigata all'interno di ogni WP, nell'ottica di una riduzione dei costi guardando ad una economia circolare attraverso studi di life cycle assessment (LCA) (WP4). Il dettaglio di ogni singola LA viene rimandato alle specifiche deliverable, prodotte separatamente dal presente documento.

Electrocatalysts of the type Pt-IrO2 (at different concentrations) have been synthesized and characterized in Regenerative Fuel Cell (RFC) configuration. Commonly IrO2 has been mainly used as oxygen evolution electrocatalyst. These oxide-metal mixtures were prepared by incipient wetness technique and characterized by XRD and SEM, obtaining in all cases nanoparticles. The powder materials were impregnated by hot-spray technique on Nafion 117 in order to evaluate water electrolysis/fuel cell performance. The catalyst loading in oxygen electrodes was about 6 mg•cm-2. Water electrolysis/fuel cell performance has been evaluated using a single cell test fixture with a geometric area of 5 cm2. It is derived that for fuel cell operation an excess of Pt favours the oxygen reduction process whereas IrO2 promotes oxygen evolution.

A flexible electrospun carbon nanofiber (CNF)-based electrode decorated with Mn3O4 is prepared starting from a solution containing polyacrilonitrile (PAN) mixed with manganese acetate (Mn(OAc)2). A thermal treatment at 270°C in air and a subsequent at 900°C in inert gas allow to obtain a flexible electrospun carbon nanofibers decorated with spinel manganese oxide (denoted as Mn3O4/CNF) characterized by suitable performance for vanadium redox flow battery (VRFB) application. Pristine electrospun carbon nanofibers CNF were prepared by using a similar method to compare the electrochemical data with respect to the decorated CNF. A homogeneous distribution of the metal oxides on the carbon nanofibers is showed by scanning electron microscopy (SEM) analysis. Cyclic voltammetry (CV) curves show a higher electrocatalytic activity toward the [VO]2+/[VO2]+ as well as the V2+/V3+ redox reactions with respect to the pristine electrospun CNF electrode, both in terms of peak to peak separation, DE[VO] 2+ /[VO 2 ] + = 0,15 V vs. 0,28 V, and Ipa/Ipc[VO] 2+ /[VO 2 ] + ratio, 1,48 vs 1,58, respectively. The improved performance is attributed to the hydrophilicity enhancement due to the oxygen groups availability that favour the surface mechanism process on the carbon nanofibers decorated with metal oxide nanoparticles.

Thermically treated graphene oxides (TT-GOs) are obtained at different temperatures, 100°C, 150°C, 200°C and 300°C in reduced environment. Physico-chemical characterizations were carried out to evaluate the electrochemical results in terms of reversibility and electrochemical impedance spectroscopy (EIS) in a three electrode half-cell. The TT-GO sample treated at 100°C (TT-GO-100), characterized by the presence of hydroxyl (-OH) and carboxyl (-COOH) species, shows an higher reversibility towards the VO2+/VO2 + redox reactions with respect to the all investigated samples. The electrochemical performance results confirm how the hydroxyl and carboxyl species prevalence play a fundamental role as active sites for the [VO]2+/[VO2]+ redox reaction process. The TT-GO-150, TT-GO-200 and TT-GO-300 sample, characterized by the prevalence of carbonyl species, phenolic (C-OH) and epoxide groups (C-O-C) on the basal plane of the structure, show a lower reversibility attributable to the higher ohmic and charge transfer resistances.

Composite Nafion-based membranes, containing 5 wt % of high-purity mesoporous titania with an average pore size of about 3.5 nm heated to 350, 450, and 600 degrees C as a filler were successfully recasted. Field emission scanning electron microscopy observations showed a high degree of dispersion of mesoporous titania particles in Nafion. Direct methanol fuel cell investigation of such membranes at temperatures higher than 100 degrees C revealed a considerable influence of the presence of the ceramic oxide and of its specific surface area on the electrochemical behavior. The composite membranes allowed operation up to 145 degrees C, showing a significant performance improvement with respect to pure Nafion. At 145 degrees C with oxygen feed, a power density of about 335 mW/cm(2) was recorded for the composite Nafion-based membranes, containing 5 wt % of mesoporous titania calcined at 450 degrees C. (c) 2005 The Electrochemical Society. All rights reserved.

High surface area carbon supported bimetallic Pt-Fe and Pt-Ru alloy catalysts have been investigated for the oxygen electro- reduction and methanol oxidation , respectively, in low temperature direct methanol fuel cells (30-60 {degree sign}C). The cathode electrocatalyst was prepared by using a combination of colloidal and incipient wetness methods. For both anode and cathode catalysts, carbon supported bimetallic nanoparticles with particle size of 2-3 nm were obtained. These materials were studied in terms of structure, morphology and composition by using XRD, XRF and TEM techniques. The oxygen reduction and methanol oxidation processes were in-situ investigated in a DMFC device. For the oxygen reduction, the electrochemical data obtained with the Pt-Fe/C catalyst were compared to those obtained in the presence of a Pt/C catalyst characterised by the same concentration of active phase on carbon and similar particle size. An enhancement of the DMFC single cell performance was recorded with the Pt-Fe/C catalyst. It was observed that the ionomer loading play a significant role in determining the performance of the DMFC. The highest power density was recorded with electrodes containing 25% Nafion loading (~90 mW cm-2 at 60 {degree sign}C).

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Polymer electrolyte fuel cell stacks assembled with Johnson Matthey Fuel Cells and SolviCore MEAs based on the AquivionTM short-side chain, chemically stabilized perfluorosulfonic acid membrane were investigated in the framework of the Autobrane EU project. Electrochemical experiments in fuel cell short stacks were performed under automotive conditions at pressures of 1-1.5 bar abs. over a wide temperature range, up to 130 {degree sign}C, with varying levels of humidity (down to 18% R.H.). The stacks using the first set of large area MEAs showed elevated performance in the temperature range from ambient to 100 {degree sign}C (cell power density in the range of 600-700 mWcm-2) with a moderate decrease above 100 {degree sign}C. The performances and electrical efficiencies achieved at 110 {degree sign}C (cell power density of about 400 mWcm-2 at an average cell voltage of about 0.6 V) are promising for automotive applications. Further optimization of stack components to maximize the high temperature performance is currently underway.

An electrochemical investigation has been carried out by using ethanol as alternative liquid fuel to methanol in a Direct Alcohol Fuel Cell (DAFC). Although methanol shows better performance with respect to ethanol, this latter represents a suitable fuel for DAFC; it is not toxic, it can be obtained from biomasses and it has a theoretical mass energy density larger than methanol. 85%Pt-Ru/C and 60%Pt/C in-house catalysts have been prepared for ethanol electro-oxidation and oxygen electro-reduction reactions, respectively, by the sulfite complex route. A composite membrane composed by Nafion ionomer and silica was fabricated in order to maintain the advantageous water retention properties of these materials at high temperatures (90-145{degree sign}C). The electrochemical behaviour of the composite membranes was also investigated in DEFCs at low temperatures (60-80{degree sign}C).

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To the Editor.— We observed an adult patient with sequential development of mucosal lesions typical of cicatricial pemphigoid (CP) and skin lesions clinically suggestive of early, urticarioid bullous pemphigoid (BP). Direct immunofluorescence showed a linear IgA deposition at the dermoepidermal junction in both lesions. The patient did not respond either to the classic combined treatment with diamino-dimethyl-sulfone (DDS) and steroids or to immunosuppressive agents. Interestingly, on the contrary, the mucosal and cutaneous lesions showed a specifically different response to different treatments, ie, the lesions were satisfactorily cured by low doses of tetracyclines and oral steroids, respectively. A 61-year-old man was first seen in 1986 with erythematous and erosive lesions of the conjunctival, oral (Fig 1), prepucial, and epiglottal mucosa for 8 months. Major symptoms consisted of burning and clear reduction of smell and taste sensitivity. Histologic examination, performed on a prepucial biopsy specimen, showed a subepithelial bulla and a perivascular

Various recast Nafion® composite membranes containing ceramic oxide fillers with different surface characteristics (SiO2, SiO2-PWA, Al2O3, ZrO2) have been investigated for application in high temperature direct methanol fuel cells (DMFCs). Cell resistance at 145 °C increases as a function of the pH of slurry of the inorganic filler indicating a strong influence of the acid-base characteristics on the electrolyte conductivity. This effect has been attributed to the different water retention capabilities of the various membranes. Fuel cell performance at 145 °C, expressed as both maximum power density and current density at 0.5 V cell potential, increases almost linearly as the pH of slurry of the oxide materials decreases. Appropriate selection of the surface properties for the inorganic fillers allows to enhance the proton conductivity and extends the operating temperature range of composite membranes. An infrared spectroscopic investigation of inorganic fillers employed in composite membranes has been carried out. The surface acidity of the fillers appears to influence the bending and stretching vibrational frequencies of the water physically adsorbed on the filler surface. Inorganic fillers characterised by acidic properties undergo a strong interaction with water and enhance the DMFC performance at high temperature.

Composite Nafion membranes containing various amounts of TiO2 (3%, 5% and 10%) were prepared by using a recast procedure for application in high temperature Direct Methanol Fuel Cells (DMFCs). The electrochemical behaviour was compared to that of a membrane-electrode assembly (MEA) based on a bare recast Nafion membrane. All the MEAs containing the Nafion-titania membranes were able to operate up to 145°C, whereas the assembly equipped with the bare recast Nafion membrane showed the maximum performance at 120°C. A maximum power density of 340 mW cm-2 was achieved at 145°C with the composite membrane in the presence of oxygen feed, whereas the maximum power density with air feed was about 210 mW cm-2.