Search

To respond to the need of flexible energy storage systems, able to provideboth power and energy services, Hybris project proposes theintegration of an organic redox flow (ORFB) battery with a lithium titanate oxide (LTO) one. Before starting with the design development (WP2), a clear picture of the current available technologies is necessary to address the integration process towards the most appropriate and feasible way. In this document, the requirements and specifications of both LTO and ORFB batteries are analysed, in terms of electrical, electronics, communication, and mechanical characteristics. Moreover, since the hybrid system will perform not only services from the owner point of view, but it will be designed to provide energy services to external requests (DSO), following the paradigm of “Energy as a Service” (EaaS), particular attention will be paid to the requirements for the interoperability. Finally, first assumptions on the technical hybridization and of the overall performance of the hybrid are part of this report.

11 figures, 2 tables.-- Supplementary data available.-- © 2022. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/, A MnCo2O4 catalyst supported on nitrogen-doped carbon nanofibers (CNF) obtained in a single-step electrospinning process is presented. MnCo2O4/CNF is investigated as bifunctional electrode for the electrocatalysis of oxygen in metal-air batteries. Crystallographic structure, morphology, and surface properties are analyzed using solid-state characterization techniques that reveal the presence of a 20 nm-particle-sized spinel and a large amount of oxidized metal species (Mn4+ and Co3+). These features are correlated with the electrochemical behavior for the oxygen reduction (ORR) and oxygen evolution (OER), showing good performances in particular for the OER compared with IrO2, benchmark catalyst for this reaction. Results revealed a synergistic effect of the catalytically active nitrogen-doped carbon nanofiber and the manganese and cobalt active species from the spinel, being responsible for the remarkable reversibility of this catalyst (ΔE = 799 mV), outperforming most of the previous works in the literature on this type of manganese/cobalt-based spinel materials. A preliminary test of an alkaline Zn-air battery equipped with this catalyst at the oxygen (positive) electrode confirms proper activity and stability during cycling operations typical of these rechargeable devices. Besides, the spinel-nanofiber-based catalyst has been produced by an easily-scalable electrospinning process, representing an advance of the current technology on positive electrodes for metal-air batteries. The curated synthesis of our MnCo-N-CNF spinel is fundamental to obtaining a catalyst with a high intrinsic catalytic activity (determined by rotating disk electrode) and an appropriate performance in a relevant environment (both gas diffusion electrode and Zn-air battery)., The research leading to these results has received funding from the ‘Accordo di Programma CNR-MiSE, RdS PTR 2019-2021 - Progetto 1.2: Sistemi di accumulo, compresi elettrochimico e power to gas, e relative interfacce con le reti’.

Poster presented at the HYCELTEC 2019 conference, VII Symposium on Hydrogen, Fuel Cells and Advanced Batteries, 1-3 july 2019, Barcelona (Spain).

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”.

9 figures, 3 tables; © 2020. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/, In the present work, an iron-cobaltite spinel supported on N-containing carbon nanofibers (CNFs) shows a remarkable activity for the oxygen evolution reaction (OER) in alkaline solution, with an overpotential (η10mAcm-2) of 130 mV, one of the lowest values in literature so far. This material is also an excellent catalyst for the oxygen reduction reaction (ORR), what leads to an extraordinary reversible behavior (ΔE = EOER – EORR=480 mV), being an economic and easy scalable candidate for the air electrode of metal-air batteries or for electrochemical devices where the oxygen evolution or the oxygen reduction is involved. In the present research, Fe partially replaces Co atoms in the Co3O4 spinel structure to obtain a more economically feasible material, leading to a FeCo2O4/CNF, by using an electrospinning preparation procedure previously adopted for the Co3O4/CNF synthesis. The substitution of iron in the Co3O4/CNF spinel entails an outstanding onset potential toward the OER of 1.36 V vs. reversible hydrogen electrode, which is 120 mV lower compared with the pure spinel (Co3O4/CNF). An optimal distribution of the FeCo2O4 particles on the CNF surface, with 3-nm-size particles, allows exposing abundant active sites, mainly Co3+ and Fe3+, responsible for the enhanced activity toward the OER, and Fe-Nx moieties and N-sites (N-graphitic/pyridinic), more active for the ORR. Besides, FeCo2O4/CNF shows a well-developed porous structure, favoring the mass transfer, a parameter particularly important for the ORR. To assess the stability of the catalysts for rechargeable alkaline metal-air batteries, cycling operation and chronopotentiometric experiments are carried out, showing a stable potential for 24 h., The research leading to these results has received funding from the ‘Accordo di Programma CNR-MiSE, RdS PTR 2019–2021 - Progetto 1.2 Sistemi di accumulo, compresi elettrochimico e power to gas, e relative interfacce con le reti’. C.A. thanks the Ministry of Economy, Industry and Competitiveness for her research contract Juan de la Cierva (IJCI-2017-32354).