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Fuel cells (FCs) are among the key technologies that Europe will have to rely on in order to comply with the most recent environmental targets inspired by decarbonization and circular economy. The assessment of the real advantages of using FCs for producing energy must include a reliable analysis of the energy and environmental impacts during the life cycle of these systems, including the raw materials supply, production, use, and disposal. In this context, the life cycle assessment (LCA) is a well-established methodology for assessing the eco-profile of products and services and for identifying the components and the life cycle steps having the largest contribution to energy and environmental impacts. In the chapter, authors focus on the analysis of two types of FCs: solid oxide FCs and polymer electrolyte membrane FCs. Authors describe the FC technology, the sectors of application, and the FC materials and components. A literature review of available LCA researches is also discussed to point out the environmental impacts of the FCs and the methodological issues that can arise in the study of a FC.

Producing green hydrogen by electrolysis is a goal at European and international level. But hydrogen production by water electrolysis is currently more expensive respect the steam methane reforming. Based on our previous studies, extra revenues in order to reduce the production costs could be obtained by considering the co-produced oxygen. Starting from the point of view of a hypothetical enterprise that needs gaseous oxygen for its activity, in order to meet a variety of requests or applications, a financial evaluation of different sizes of RES-based electrolytic plant (100 kW - 10 MW) is proposed. The most relevant result that emerged from our research is the economic sustainability of the investment if the market price of oxygen is at least 3 EUR/kg. In this case, the self-production of oxygen results to be convenient, whatever the size of the electrolyser. This is valid for both the two scenarios assumed, with the exceptions of the smaller electrolyser sizes (

As emphasised by the crisis caused by the COVID-19 pandemic, medical oxygen is an essential health commodity. The purpose of this study is the application of Renewable Energy Sources (RES)-based (photovoltaic-powered) water electrolysis plant for oxygen production in hospitals to self-produce the amount of oxygen they need, and – in particular – to define when this choice could be economically competitive with the current medical gas market. The proposed plant is able to produce oxygen and to store energy in hydrogen form at the same time, proposing a new approach in RES applications. Therefore, we calculated as a function of the hospital size (number of beds, up to 500) what should be the market price of oxygen above which the self-production of oxygen is economically profitable (assuming a break-event point of 15 years). Hydrogen is considered a by-product allowing to increase the system efficiency and supplying extra services. The results demonstrated that, assuming a selling price of 3 €/kg for the hydrogen (co)-produced by the plant, the on-site production of medical oxygen could be an interesting alternative compared to purchasing from the local gas resellers, if its market price is higher than 3–4 €/kg. Since this value is in line with current prices established for ex-factory oxygen by some national regulatory authorities (e.g., AIFA), we can conclude that the proposed RES-based electrolysis system is a green and economically feasible solution for oxygen production in hospitals, able also to increase hospital resilience against energy and oxygen shortage.

Today, worldwide hydrogen production (around 70 Mt/year, in 2018) is almost exclusively (96%) derived from fossil fuels, with water electrolysis accounting for a residual share (4%) [1]. But, the conventional processes used for hydrogen generation - mainly, steam methane reforming (SMR) - are responsible for about 5% of the global carbon dioxide emissions [2]. By contrast, water electrolysis powered by renewable energy sources (solar, wind, etc.) is a mature and environmentally friendly technology for large-scale hydrogen production, whose main bottleneck for a widespread diffusion is still related to economic concerns [3]. In fact, according to the literature [4, 5], the production cost of hydrogen from electrolysis is at least 5-6 EUR/kg, which is not competitive compared with hydrogen production by SMR (ca. 1.5-2.3 EUR/kg [6]). In our previous investigations [7, 8], we performed some evaluations of a system based on alkaline water electrolysis (180 kW) coupled with a photovoltaic plant (200 kW), looking at the oxygen valorisation for reducing hydrogen production costs. These studies allowed us to demonstrate the economic profitability of the system when the extra revenues generated from the selling of the co-produced oxygen (usually vented into the atmosphere) are considered. Recently [9], we completely reversed the usual concept, and considered a photovoltaic-powered electrolysis plant whose main purpose was to satisfy the oxygen requirements of a hypothetical enterprise, while the obtained hydrogen could be sold to external users to achieve additional revenues. The obtained results evidenced that the proposed plant was economically attractive if compared to the case when the same enterprise buys the compressed oxygen from local gas distributors/resellers. In particular, by assuming a hydrogen selling price of 10 EUR/kg (a reference price for hydrogen as a fuel, at the pump), the economical sustainability (recovery of the investment within 20 years) is achieved if the market price of oxygen is at least 3 EUR/kg, whatever the size of the electrolyser (in the range from 100 kW to 10 MW). Nowadays, the energy-health nexus is a key theme whose importance and priority cannot be neglected or postponed anymore. The availability and quality of energy supply affect the quality of primary healthcare, and some studies [10] evidenced that sustainable decentralized renewable energy technologies could bridge the gap for access to healthcare in medical centres located in remote areas. In addition, due to the current COVID-19 pandemic, the demand for oxygen increased - e.g., in parts of Italy, oxygen consumption has tripled [11] - and this has exacerbated the shortage of medical oxygen in many developing countries [12]. Based on these considerations, in this work we consider an electrolysis plant devoted to gaseous oxygen generation for a typical medium-size hospital (200-250 beds capacity) and, assuming that the hydrogen produced from the plant is sold at 3 EUR/kg (a price competitive with hydrogen from fossil fuels), we perform some calculations to estimate what should be the (market) price of oxygen to achieve economic profitability within 15 years through the oxygen self-production from the proposed system.

Poly-generation is meaning as the generation of different forms of energy by the same machine/system. This concept is applied in distributed generation from renewable energy sources (RES) for increasing the conversion efficiency, in particular looking at near-zero energy buildings. In this case, usually, batteries are used for storing excess RES energy production and using it during lack of energy periods. Looking at hydrogen, nowadays, it is worldwide accepted that storing RES power as hydrogen is the best way to fulfil the expectation of a greener future and addressing the ambitious targets of greenhouse gas emission reduction. In the present work, we propose a new concept of poly-generation based on hydrogen technologies. In this new vision both energy and goods are produced from RES. In particular, we propose a poly-generation system able to supply electric energy, thermal energy (heat and cooling), and H2/O2 co-production. So that the proposed system is able to produce different forms of energy and also goods (hydrogen and oxygen) giving a new sense to the concept of RES-polygeneration. Water electrolysis powered by renewable energy sources (solar, wind, etc.) is a mature and environmentally friendly technology for large-scale hydrogen production (green hydrogen), whose main bottleneck for widespread diffusion is still related to economic concerns. In fact, based on the literature, the production cost of hydrogen from electrolysis is at least 5-6 EUR/kg, which is not competitive compared with hydrogen production by SMR (ranging from about 1.0 to 2.3 EUR/kg, according to the literature). As highlighted in our previous publications, one of the main lack in the usual calculations of green hydrogen costs is that oxygen is typically considered a not useful good and it is released in the atmosphere. In the same studies, we performed financial evaluations demonstrating that by valorising the produced oxygen it is possible to strongly reduce the production cost of hydrogen. Here, we propose a system able to produce energy (in different forms), hydrogen and oxygen. Moreover, a case study was selected for demonstrating the financial viability of this system. In the case study, a simplified system is applied to an Italian hospital and it is addressed to supplying only medical oxygen and hydrogen, opening also a new vision on the RES-health nexus. The results show that the simplified system is economically viable, moreover by this approach the production cost of green hydrogen is strongly reduced, up to less than 1 EUR/kg, becoming largely competitive with steam reforming production. Economic studies on the full system are running.

Thermotoga neapolitana (DSM 4359, ATCC 49049), more than others Thermotogales is able to accumulate biohydrogen from waste organic matter, in a selective environment (>80ºC). Thanks to the high temperature, this bacterium is able to use a peculiar anaplerotic biochemical pathway named Capnophilic Lactic Fermentation (CLF) that accomplishes chain elongation of acetate with direct reduction of CO2, producing lactic acid (Pradhan et al. 2015). This is a carbon fixation mechanism which, differently from autotrophism, leads to direct elimination of fixed carbon into excreted metabolites, such as lactic acid, instead of converting and accumulating it into biomass. T. neapolitana is therefore a promising microorganism for recovering added-value chemicals from organic wastes (Fontana, EP14711847.5). In this work, the possibility of bioelectrostimulate the production of lactic acid by Thermotoga Neapolitana supplying additional electric energy in polarized and unpolarized bioreactors is investigated. For this, an alternating polarization up to ±1.2V was imposed between two identical electrodes of carbon cloth, immersed in the electrochemical bioreactors. Bioreactor without electrodes were also tested, as control. Glass reactors of 250 mL were operated at temperature of 85°C with a culture media of T. neapolitana containing 5 g/L (~30mM) of glucose, in triplicates. Three successive cycles of chemical measurements was carried out every 24 hours for three measurement cycles, to estimate the glucose consume and the acetic/lactic acid production, as well the hydrogen yieldin each tested bioreactor. The solution Optical density (OD) and micrographs produced by scanning electrode microscopy (SEM) showed a strong affinity of bacteria to form biofilm on the polarized and unpolarized electrodes. Evidence of the lactate/acetate ratio modification with respect the control bioreactors was achieved, especially under higher polarized condition, but also in the bioreactors with unpolarized electrodes. Glucose fermentation was strongly inhibited in electrochemical bioreactors in the first 24-48 hours test and during the whole three days test in some cases. Only in the control bioreactor glucose was oxidized to acetic acid in the molar rate similar to dark fermentation (glucose:acetic 1:2) and only the first day. Lactic acid in a relative high ratio versus the glucose consume, although at lower concentration with respect acetate, was found especially in some polarized bioereactors. These results globally confirm the affinity of Thermotoga neapolitana to carbon cloth electrodes and the possibility of electrostimultate their metabolism, opening future perspectives on electro-fermentation with this hyperthermophilic strain. Pradhan N., Dipasquale L., et al. 2015, Int. J. Mol. Sci. 16, 12578-12600 Fontana EP EP14711847.5. EU patent application: EP14711847.5; Priority IT20130109 24/01/2013 d’Ippolito G, Dipasquale L, Vella FM, Romano I, Gambacorta A, Cutignano A, Fontana A. Int J Hydrogen Energy 2010;35:2290–5. doi:10.1016/j.ijhydene.2009.12.044.

Hyperthermophile bacteria were seldom investigated in bioelectrochemical systems although they allow more effective control of the inoculum in comparison with mesophilic bacteria. Biofilm formed in hyperthermophilic conditions (>60 °C) also rarely was documented (d'Ippolito et al., 2020; Belkin et al., 1986, Pysz et al., 2004). Scanning Electron Microscopy (SEM) micrographs documenting biofilms formed by the Hyperthermophile bacterium Thermotoga neapolitana on different solid materials (ceramic carrier, stainless steel mesh, carbon felt, carbon paper, expanse graphite, and carbon cloth) are shown in this report. Also, micrographs of the biofilm formed on electrodes of carbon cloth under a dynamic polarization oscillating around ±1 V (±0.8 V and ±1.2 V) are reported. Two procedures of sample preparation for SEM analyses are described and used: 1) a fast drying of samples, which is enough to underline the biofilm shape that covers solids, and 2) a chemical treating of the samples with glutaraldehyde, which better preserves the shape of bacterial cell components in the biofilm, although this treatment might cause the detachment of pieces of the biofilm. The different effect of potentiostatic and potentiodynamic polarizations on the glucose metabolism of T. neapolitana has been screened and discussed in the associated article [1] . Here, data of Optical Densities (O.D.) of culture media are provided, indicating the presence or absence of bacteria growth in the bulk of the media. Data have been collected every 24 h from the differently polarized bioreactors. The electrodes set-up of small bioreactors is also illustrated. Chemical data, optical data and SEM images, accordingly, document a retard in the glucose fermentation process due to a settlement of T. Neapolitana in a stationary phase. The polarization of electrodes can modify the stationary condition, inducing a possible change of the bacteria metabolism.

This deliverable maps the prevailing polycentric settings of six studied countries. The studied countries are the partner countries for the NEWCOMERS project, i.e. Germany, Italy, the Netherlands, Slovenia, Sweden and the United Kingdom. In this report, the countries' polycentric settings will be described in relation to the polycentric framework developed in WP 2, with specific focus on the technical system and actors. The factors in focus for the country descriptions are socio-economic conditions, technical system (electricity and heat), institutional arrangements as well as actors. Additionally, a description of energy communities in each country is presented, showing different developments in this area. The research was conducted through a desktop research. Existing literature, reports as well as statistical information were gathered and then organised according to the factors chosen. The aim in this delivery is to describe and understand the national polycentric settings as a first step to understand the emergence of new forms of energy communities. This deliverable is the basis for delivery 3.2, which will compare different polycentric national settings and delivery 3.3, which will evaluate what forms of energy communities work best in different polycentric setting and what are the potentials for learning between different polycentric settings.

The weather-dependent electricity generation from Renewable Energy Sources (RES), such as solar and wind power, entails that systems for energy storage are becoming progressively more important. Among the different solutions that are being explored, hydrogen is currently considered as a key technology allowing future long-term and large-scale storage of renewable power. Today, hydrogen is mainly produced from fossil fuels, and steam methane reforming (SMR) is the most common route for producing it from natural gas. None of the conventional methods used is GHG-free. The Power-to-Gas concept, based on water electrolysis using electricity coming from renewable sources is the most environmentally clean approach. Given its multiple uses, hydrogen is sold both as a fuel, which can produce electricity through fuel cells, and as a feedstock in several industrial processes. Just the feedstock could be, in the short term, the main market of RES-based hydrogen. In this paper, we present the results obtained from a techno-economic-financial evaluation of a system to produce green hydrogen to be sold as a feedstock for industries and research centres. A system which includes a 200 kW photovoltaic plant and a 180 kW electrolyser, to be located in Messina (Italy), is proposed as a case study. According to the analyses carried out, and taking into account the current development of technologies, it has been found that investment to realise a small-scale PV-based hydrogen production plant can be remunerative.

Photoelectrochemical water splitting is a green, sustainable technology for harnessing solar energy to generate H-2; however, the energy demand needed to drive this non-spontaneous reaction limits the technology's competitiveness. In addition, the poor efficiency of photoanodes in photoelectrochemical cells (PECs) has been one of the factors governing the overall solar conversion efficiency of PECs. Here, a novel stacking approach of n-type titanium dioxide nanotubes (TiO2 NTs) photoanodes was proposed to improve their light-harvesting and charge transfer properties. Interestingly, the stacked photoanodes exhibited a much higher photocurrent of -0.79 mA/cm2 at 1 V (vs. SHE) than single sheet TiO2 NTs photoanode (i.e., -0.07 mA/cm(2)) at the same po-tential, implying that TiO2 NTs stacking approach resulted in effective light absorbance and management and much lower charge transfer resistance across the interface of photoanode and electrolyte. In addition, a self-biased, integrated solar-microbial system was developed, in which a microbial fuel cell (MFC) fed with real animal manure wastewater was used as a power source to drive sustainable H-2 production in a photo-electrochemical cell having stacked TiO2 NTs photoanodes. Without any external bias, the integrated system, which comprises an MFC and a three-sheet TiO2 NTs photoanode-based PEC, generated a photocurrent of 0.44 mA/cm(2) with an H-2 production rate of 0.45 +/- 0.03-m(3) H-2/m(3) day under 1 sun illumination (100 mW/cm(2)), which is -1.5-1.9-fold higher than other tested systems. This study demonstrates the synergetic effect between MFCs and PECs, in which electrons recovered from wastewater biodegradation in MFCs significantly increase H-2 generation in PECs without the need for an external power source.

This paper presents the optimization of the driving strategy of a high efficiency fuel cell based power train. This power train is developed to equip a light duty urban-concept vehicle that runs energetic races. The objective is to go the furthest with the lowest quantity of fuel. A comprehensive dynamical model is presented, including the mechanical requirement, the thermal behavior of the fuel cell stack and the various losses and consumptions of the power train devices. This model is next integrated into a global optimization algorithm, to determine the best race strategy to be adopted. These results are validated on experimental measurements, obtained during a real race at the Shell Eco-Marathon, in 2015.

Electrodes based on activated carbon and manganese oxide coated on a cotton woven fabric were developed and investigated. The electrodes were then assembled with two polymer electrolyte membranes, Nafion®115 and Aquivion®E87-05S, and two different supercapacitors were produced with specific capacitances and energy densities of 130 and 132 F g−1, and 11.5 and 11.7 Wh kg−1, respectively. Furthermore, a new durability methodology, which combines galvanostatic charge/discharge cycles together with potentiostatic floating conditions, was used to get insight into their electrochemical performance under stringent conditions. The supercapacitor assembled with Nafion®115 electrolyte worked successfully for 10 k cycles and 140 h under a constant voltage of 1.6 V (floating condition), whereas the supercapacitor assembled with Aquivion®E87-05S electrolyte worked successfully for more than 15 k cycles and 210 h, without any appreciable degradation of their electrochemical properties. In summary, hybrid solid-state supercapacitors based on electrodes produced by simple methodologies and low-cost materials, and with long durability performance under very harsh conditions were developed and analysed for their potential utilization as flexible energy storage devices., This work was supported by Project UID/CTM/00264/2019 of 2C2T – Centro de Ciência e Tecnologia Têxtil, funded by National Founds through FCT/MCTES. This research was also partially supported by the Cost Action 15107, Grant No. ECOST-STSM-CA15107-300118-092731.

The goal that the international community has set itself is to reduce greenhouse gas (GHG) emissions in the short/medium-term, especially in Europe that committed itself to reducing GHG emissions to 80–95% below 1990 levels by 2050. Renewable energies play a fundamental role in achieving this objective. In this context, the policies of the main industrialized countries of the world are being oriented towards increasing the shares of electricity produced from renewable energy sources (RES). In recent years, the production of renewable energy has increased considerably, but given the availability of these sources, there is a mismatch between production and demand. This raises some issues as balancing the electricity grid and, in particular, the use of surplus energy, as well as the need to strengthen the electricity network. Among the various new solutions that are being evaluated, there are: the accumulation in batteries, the use of compressed air energy storage (CAES) and the production of hydrogen that appears to be the most suitable to associate with the water storage (pumped hydro). Concerning hydrogen, a recent study highlights that the efficiencies of hydrogen storage technologies are lower compared to advanced lead acid batteries on a DC-to-DC basis, but “in contrast […] the cost of hydrogen storage is competitive with batteries and could be competitive with CAES and pumped hydro in locations that are not favourable for these technologies” (Moliner et al., 2016) [1]. This shows that, once the optimal efficiency rate is reached, the technologies concerning the production of hydrogen from renewable sources will be a viable and competitive solution. But, what will be the impact on the energy and fuel markets? The production of hydrogen through electrolysis will certainly have an important economic impact, especially in the transport sector, leading to the creation of a new market and a new supply chain that will change the physiognomy of the entire energy market.

The possibility of electrostimulate the production of lactic acid by Thermotoga neapolitana settled on electrodes is investigated in this work. Three days experiment was conducted supplying an alternated electric energy in polarized and unpolarized bioreactors fed with 30mM of glucose. The solution Optical density decrease and documentation produced by scanning electron microscopy micrographs showed a strong affinity of bacteria to form biofilm both on the polarized and unpolarized electrodes. Evidence of the lactate/acetate ratio modification with respect the control bioreactors was achieved, both for polarized and unpolarized bioreactors. These results globally confirm the affinity of T. neapolitana to carbon cloth electrodes and the possibility of electrostimultate their metabolism, opening future perspectives on electro-fermentation with this hyperthermophilic strain.

Introduction to the special issue on EFC17

Generation of bio-hydrogen is a new frontier in hydrogen production field. A number of bacteria have been considered for this purpose. Within these we have studied Thermotoga neapolitana (DSM 4359, ATCC 49049) strain, a rod-shaped, gram-negative, non-sporulating, anaerobic bacterium that is able to release bio-hydrogen and produce lactic acid from waste organic matter, in a selective environment (>80ºC).1,2 These performances make the bacterium suitable for biotechnology applications of energy interest. As reported by Kelly and coworkers, the congener hyperthermophilic bacterium Thermotoga maritima is able to form biofilm in bioreactor glass walls or on nylon mesh, and polycarbonate filters in maltose-based media at 80 degrees C. Most notably, T. maritima biofilm-bound cells exhibited increased transcription of genes involved in iron and sulfur transport, as well as in biosynthesis of NAD/NADH and isoprenoid side chains of quinones. Redox mediators are involved in these chains and this suggests the possibility of using biofilm forming strains for bio-electrochemical applications. For this purpose a key, still unresolved challenge is the formation of biofilm on conductive materials. The formation of biofilms depends on the type of surface to adhere. The capability of hyperthermophilic and strictly anaerobic Thermotoga neapolitana to adhere on different materials was investigated in this work. Different geometries of conductive and not conductive substrates have been tested for inducing biofilm of Thermotoga neapolitana including carbon based woven and not-woven fabrics, metallic fabric and coated materials. A selected material was used for inducing electrical stress with the aims of verify if T. neapolitana is sensible to electro-stimulation. The results demonstrated the Thermotoga neapolitana aptitude to attach on conductive graphite as well as on porous alluminosilicate. Time differences in the biofilm evolution were detected, main depending of the material characteristics. Test on carbon based electrodes supported changes in the final fermentation products in respect to the reference process under standard conditions.

It is a common opinion that the renewable sources play a primary role to reduce the greenhouse gas (GHG) emissions and that, according to the IEA, solar may become the largest source of low-carbon electricity capacity by 2040, when the share of all renewable energy sources (RES) in total power generation would reach 40%, led by China and India. In the European Union, soon after 2030, renewables will account for 80% of new capacity and wind power becomes the leading source of electricity, due to strong growth both onshore and offshore (IEA, 2017). The weather-dependent electricity generation from RES entails that systems for energy storage are becoming increasingly important. Among the various solutions that are being evaluated, hydrogen is currently considered to be one of the key enabling technologies allowing future large scale and long term storage of renewable power. At present, hydrogen is mainly produced from fossil fuels, and steam methane reforming (SMR) is the most widely used route for producing hydrogen from natural gas. None of the conventional methods used is GHG-free. The Power-to-Gas concept, based on water electrolysis utilizing electricity derived from renewable energies is the most environmentally friendly approach. Given its multiple uses, hydrogen is sold both as a fuel, which can produce electricity through fuel cells, and as a feedstock in several industrial processes. Just the feedstock could be, in a short term, the main market of RES-based hydrogen. In this paper, we present the results obtained from a techno-economic-financial evaluation of a system to produce green hydrogen to be sold as a feedstock for industries and research centres. We proposed, as a case study, a system which includes a 200 kW photovoltaic plant and a 180 kW electrolyser, to be located in Messina (Italy). According to our analyses, and taking into account the current development of technologies, we found out that an investment to realize a small-scale PV-based hydrogen production plant can be remunerative.

Hyperthermophile bioelectrochemical systems are seldom investigated although their superior control of microbial consortium and thermodynamic advantages. Hyperthermophilic Thermotogales, for instance, are able to produce hydrogen and lactic acid from wastes better than mesophilic bacteria. Here, the electrostimulation of Thermotoga neapolitana in single-chamber electrochemical bioreactors is studied. The glucose fermentation under CO2 pressure, as model metabolism, was tested at 80 °C. Results show that a dynamic polarization (±0.8 to ±1.2 V) drives glucose fermentation and biofilm stasis on electrodes. Under this condition, production of lactic acid (33 vs 12 mM) and yields of acetate and hydrogen (with lactic/acetic acid ratio of 1.18) were higher than those achieved with static polarization or open-circuit. Dynamic polarization is possibly exploitable to stimulate T. neapolitana in a hyperthermophile electrochemical system for various applications including control of power-to-gas processes or production of value-added products (hydrogen and lactic acid) from sugary wastes.

Every time a new material or component for a technology is developed, it must be tested before it can be mass produced. Regarding polymer electrolyte membrane fuel cells (PEMFC), if a new material or component is developed, its testing in a single cell is required for validating its effectiveness, or for optimizing its performance in terms of efficiency and endurance. To perform the testing, it is necessary to build the membrane electrode assembly (MEA). This is the argument of this chapter, wherein a review, integrated with personal experience, of possible preparation methods for laboratory-scale application is reported. The goal is to supply information that it is necessary to define a detailed procedure for efficient MEA production.

World countries have set itself to reduce greenhouse gas emissions in the short / medium term, and Europe committed itself to reducing Green House Gas (GHG) emissions to 80-95% below 1990 levels by 2050. These policies are based on the development of non-fossil energy supply and electrification. In this context, the increasing of shares of electricity produced from renewable sources is an ineluctable necessity. In recent years, the production of renewable energy has increased considerably, but given the dependance of these sources from sun daily cycle and weather, there is a mismatch between production and demand. This arises some issues as balancing the electricity grid, and in particular the use of the energy surplus and compensation of energy lacks, as well as the need to strengthen the electricity grid. Among the various new solutions that are being evaluated, there are: the accumulation in batteries, the compressed air and hydrogen storage. These solutions appear to be the most suitable to associate with the water accumulation (pumped hydro). Concernig the hydrogen, recent research highlights that the efficiency hydrogen storage thechnologies have lower performance compared to advanced lead acid batteries on a DC to DC basis, but"...In contrast, according to the cost of Hydrogen storage is competitive with batteries and could be competitive with CAES and pumped hydro in locations that are not favorable for these technologies." [1] This means that, once the optimal efficiency rate is reached, the technologies concerning the production of hydrogen from renewable sources will be a viable and competitive solution for balancing electric grid. However hydrogen is not just a storage medium like batteries and conmpressed air, it is also a fuel with a number of possible applications. Consequently, what will be the impact on the energy and fuel markets? The production of hydrogen through electrolysis will certainly have an important economic impact not only in electricity and in the transport sectors, but will lead also to the creation of a new market and new supply chains that will change the physiognomy of the entire energy market.

Fuel cells are a potential future technology that has started today, providing a change in the way heat and power are supplied to end users (Elmer in Renew Sustain Energy Rev, 2014).

In this study, we report a diagnostic technique to identify and monitor the long-term performance developments and state-of-health (SOH) of hybrid solid-state supercapacitors through electrochemical impedance spectroscopy. This technique applies a small AC signal (voltage) to the supercapacitor over a specific frequency range, which is distinctive to a supercapacitor features. The supercapacitor impedance response to the AC perturbation give information about the electrical properties of materials (current collector, electrodes, electrolyte and electrode/electrolyte interfaces) as well as faradaic and double layers capacitances of the whole cell. The different processes occurring in cell can be distinguished using impedance measurements because they can have different time constant and taken over a broad range of frequencies (i.e.: 100 kHz to 0.001 Hz). We present here the EIS study on various solid-state supercapacitors realized by contacting face-to-face a SPEEK electrolyte membrane and the two 2 cm2 carbon xerogel electrodes. In addition, a KI solution was used as additive to electrolyte and impregnate in the positive electrode, while the Na2SO4 was employed to make a cation exchange SPEEK membrane and impregnate the negative electrode. This added KI salt had the function providing additional pseudocapacitance (through I-/I3-redox reactions) overlying to the EDLC and may allow a widen voltage window, even without water electrolysis at 1.6 Volt. The studied supercapacitors were electrochemical investigated by usual cyclic voltammetry (CV), DC galvanostatic charge/discharge and as well as AC electrochemical impedance spectroscopy (EIS) and Potentiodynamic impedance (PDEIS). This latter technique was applied on the full voltage range from 0 to 1.6 V and at voltage scan of 0.2V, which can give additional information on the reversibility of different processes and that contribute to the frequency response of device. The EIS analysis highlighted that the solid-state supercapacitor had very low resistance and full capacitance retention during long-term durability test of 20 k cycles (at 2 Ag-1) and additional 300 h at maximum voltage of 1.6 Volt. Moreover, EIS and PDEIS analysis carried out a configuration of SCs with SPEEK membrane and KI redox-species shows several benefits such us exceptional long-term durability (20 K cycles and additional 300 h at constant voltage of 1.6 V), high specific capacitance (? 200 F g-1), high energy density (?20 Wh kg-1) and slow self-discharge rate. These benefits are due to lowering of the positive potential (during the stability test) that was achieved by adding redox-active (I-/I3-) species. Thus maintaining this positive electrode under the limits of oxygen evolution reaction (OER), which is about 0.8-0.9Vvs SHE, the supercapacitor can work reversibly and for long time without appreciable decay. The impedance analysis shows that during the long stability occurs a slight increase of ionic resistance, and a higher increasing of charge transfer (Rct), which can likely lead to a slight decay of EDLC contribution and an increase in pseudo capacitance so that the total capacitance remain unchanged for the supercapacitor.

In this article, the liquid water eruptive transport occurring during the water breakthrough from the Gas Diffusion Layer (GDL) of a PEMFC into the gas channel is investigated. A dedicated experimental set-up is used enabling the simultaneous measurement of pressure inside the water system and visualization of droplet formation. A single-drop capillary model is proposed to explain the eruptive nature of droplet formation. The model is built on four physical equations involving Laplace's law, a water system compressibility law, the pressure losses occurring during droplet formation, and a spherical droplet geometrical function. Two numerical resolution methods are implemented and compared. For this model, three parameters have to be identified from the experimental data. The identification procedure is explained in the paper and the comparison with experimental results shows the ability of the present model to reproduce the eruptive nature of liquid water breakthrough from the GDL.

Prefazione al volume e presentazione della congferenza

Recently, the development of high performance and cost-effective materials for electrodes and electrolytes of energy storage devices is highly desired. In this presentation, some carbon materials for electrodes and solid polymer electrolytes were studied for the fabrication of flexible solid-state supercapacitors. The supercapacitor cells were fabricated contacting face-to-face a SPEEK membrane and two 2 cm2 electrodes. The electrochemical features of these supercapacitors were investigated in a specific designed titanium cell provided of a reference electrode, which monitored the potentials of the positive and negative electrodes of the full cell working in the range from 0 to 1.6 Volt. The 1M Na2SO4 solution was used to exchange the SPEEK membrane, to impregnate a porous separator in a second type of supercapacitor; while a KI solution was added as an additive of the electrolyte on the positive electrode. The sulfonated poly(ether-ether-ketone) (SPEEK) membrane in the supercapacitors had the function of ionic conductor between electrodes and KI salt provided additional pseudocapacitance through I-/I2/I3- multiple redox reactions on the positive electrode. The designed solid-state hybrid supercapacitors were electrochemical investigated trough cyclic voltammetry (CV), DC galvanostatic charge/discharge and electrochemical impedance spectroscopy (EIS). As results of the study, it were found that the solid-state supercapacitor based on SPEEK membrane and with iodide species in the positive electrode exhibited higher specific capacitance (~200 F g-1), which was higher than supercapacitor (93 F g-1) with porous separator impregnated with 1M Na2SO4 electrolyte. The EIS and potentiodynamic impedance in-situ analysis highlighted very interesting features especially for solid-state hybrid supercapacitor based on polymer electrolyte (with KI additive). In particular, it showed high specific capacitance, low resistance, high capacity retention and long-term durability for tests up to 20000 cycles and more than 300 h in voltage holding condition at 1.6 Volt. Moreover, the EIS was also used to gain insight of electrochemical processes as the interaction between electrode and electrolyte, when the charge storage mechanism occurs also through faradaic reactions. Likewise, EIS was used to identify possible ageing mechanisms and to understand the causes of change in impedance that occurs by either the addition of new electrochemical processes or by enhancing of specific resistances of the supercapacitor. The remarkable electrochemical performances (e.g. ~ 200 F g-1, ~ 20 Wh kg-1) and exceptional long-term durability (~ 300 h at 1.6 V, under constant voltage test) demonstrated from this configuration of flexible solid-state supercapacitor are very promising for the development of next-generation low cost, high-performance, solid-state and flexible energy storage devices.

Il volume contiene gli abstract dei lavori accettati per i contributi orali e i poster presentati a HYPOTHESIS XII

Fuel cells (FCs) are among the key technologies that Europe will have to rely on in order to comply with the most recent environmental targets inspired by decarbonization and circular economy. The assessment of the real advantages of using FCs for producing energy must include a reliable analysis of the energy and environmental impacts during the life cycle of these systems, including the raw materials supply, production, use, and disposal. In this context, the life cycle assessment (LCA) is a well-established methodology for assessing the eco-profile of products and services and for identifying the components and the life cycle steps having the largest contribution to energy and environmental impacts. In the chapter, authors focus on the analysis of two types of FCs: solid oxide FCs and polymer electrolyte membrane FCs. Authors describe the FC technology, the sectors of application, and the FC materials and components. A literature review of available LCA researches is also discussed to point out the environmental impacts of the FCs and the methodological issues that can arise in the study of a FC.

The publisher regrets the poor quality of the images of Figures 2, 4 and 5, which are now corrected as below.

Summary of the lesson

Sintesi dell'attività svolta dal CNR-ITAE nell'ambito del progetto EU-FP7 ETRERA_2020 poi divenuto parte integrante del "final Report" redatto dal coordinatore di progetto.

Sintesi del supporto al progetto tramite il server fornito dall'ITAE al progetto: database di progetto e sito web della conferenza finale.

Solid-polymer electrolytes based on perfluorinated sulfonic acid (PFSA) are suitable materials to be used in the development of more compact, safer and flexible solid-state supercapacitors. For this reason we investigated two different polymer electrolytes and fabricated supercapacitors containing these materials in the electrodes and membranes. The two commercial electrolyte membranes were the Nafion 115 produced by DuPont and the Fumapem F-950 of FuMA-Tech GmbH. The polymers were also available in the form of electrolyte solutions. Thus, two electrodes were prepared by mixing an activated carbon (Norit A supra Eur) with a 5 wt% of Nafion solution by Aldrich, for the first one, and with a Fumion FLD1020 solution obtained from FuMA-Tech GmbH (Germany), for the second one. With these materials, electrodes and membranes, a series of four solid-polymer supercapacitors were assembled: 1)Electrode with Nafion/Nafion membrane/Electrode with Nafion (EN/N/EN) 2)Electrode with Nafion/Fumapem membrane / Electrode with Nafion (EN/F/EN) 3)Electrode with Fumion/Nafion membrane / Electrode with Fumion (EF/N/EF) 4)Electrode with Fumion/Fumapem membrane / Electrode with Fumion (EF/F/EF) The supercapacitors were realized in symmetric configuration, i.e., in which the two electrodes had the same loading of activated carbon material and the same kind of polymer electrolyte. The results of impedance analysis, cyclic voltammetry and galvanostatic charge/discharge evidenced that the supercapacitor, EN/N/EN, with Nafion in the electrolyte membrane and as binder/ion conductor in the electrodes, exhibited the highest electrochemical performances. In particular, this solid-polymer supercapacitor showed a specific capacitance of 115 F g-1 (see also Fig. 1) and a low resistance of 0.31 ohm cm2. All the other investigated solid state supercapacitors showed slight higher resistances and lower electrochemical performances. The best Nafion based capacitor may offer great promise in the application of solid-flexible supercapacitors, especially considering the low electric series resistance (ESR =0.31 ohm cm2) achieved by this supercapacitor.

Electrochemical methods such as voltammetry and electrochemical impedance spectroscopy are effective for quantifying solid oxide fuel cell (SOFC) operational performance, but not for identifying and monitoring the chemical processes that occur on the electrodes' surface, which are thought to be strictly related to the SOFCs' efficiency. Because of their high operating temperature, mechanical failure or cathode delamination is a common shortcoming of SOFCs that severely affects their reliability. Infrared thermography may provide a powerful tool for probing in situ SOFC electrode processes and the materials' structural integrity, but, due to the typical design of pellet-type cells, a complete optical access to the electrode surface is usually prevented. In this paper, a specially designed SOFC is introduced, which allows temperature distribution to be measured over all the cathode area while still preserving the electrochemical performance of the device. Infrared images recorded under different working conditions are then processed by means of a dedicated image processing algorithm for quantitative data analysis. Results reported in the paper highlight the effectiveness of infrared thermal imaging in detecting the onset of cell failure during normal operation and in monitoring cathode activity when the cell is fed with different types of fuels.

Summary of the lesson

This work presents the PEMFC stack design methodology developed at CNR-ITAE, in theframe of a collaboration with an industrial partner, Electro Power Systems (EPS), operatingin the Uninterruptable Power Supply (UPS) market. A detailed description of the designprocedure of a 7 kW PEMFC stack is reported, starting from technical requirements of theUPS system to experimental tests. Bipolar plate layout, active area surface and shape,maximum (OCV) and minimum voltage, maximum cooling circuit pressure drop,maximum cathodic flow-field pressure drop, were the main constraint that influenced theconstructive solutions. The electrochemical performances of Gore Primea 5621 MEA withSGL Sigracet GDL were chosen as reference to select the appropriate operating point interms of current density and single cell voltage. A current density of 800 mA/cm 2 wasimposed as operating point of the stack, subsequently main stack parameters werecalculated. Three different cathodic flow fields, that were designed to fulfill UPS systemrequirements, were tested in a single cell arrangement, to find the best gas flow path interms of compromise between cell performance and pressure drop. Also a specific studywas dedicated to the selection of gasket material to find the best compromise between cellperformance and limited mechanical stress. The assembled 70 cells unit was tested ina test bench simulating the power system. Preliminary tests of the full unit yielded toa power of 6.2kW at 36 V.a 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.

The research activity in polymer electrolyte fuel cell (PEFC) is oriented to the evolution of components and devices for the temperature range from 20 to 130 °C, and covers all the aspects of this matter: membranes and electrodes, fuel cell stack engineering (design and manufacturing) and characterization, computational modelling and small demonstration systems prototyping. Particular attention is devoted to portable and automotive application. Membranes research is focused on thermostable polymers (polyetheretherketone, polysulphone, etc.) and composite membranes able to operate at higher temperature ( > 100 ∘ C ) and lower humidification than the commercial Nafion ® , while Pt load reduction and gas diffusion layer improvement are the main goals for the electrode development. PEFC stack engineering and characterization activity involve different aspects such as the investigation of new materials for stack components, fuel cell modelling and performance optimization by computational techniques, single cell and stack electrochemical characterization, development of investigation tools for stack monitoring and data acquisition. A lot of work has been focused to the fuel cell stack architecture, assembling, gas leakage and cross-over reduction (gasketing), flow field and manifold design. Computational fluid dynamics studies have been performed to investigate and improve reactants distribution inside the cell. A flow field design methodology, developed in this framework and related to serpentine like flow field, is actually under investigation. All of these aspects of PEFC stack research are realized in the framework of National and European research projects, or in collaboration with industries and other research centres. In the present work our stack research activity is reported and the most important results are also considered.

This paper is dedicated to the optimization of the driving strategy of a high efficiency fuel cell based power train. This power train is developed to equip an urban-concept vehicle that runs energetic races where the objectives are to go the furthest with the lowest quantity of fuel (Shell Eco Marathon). Through a comprehensive dynamical model, including the mechanical requirement, the thermal behavior of the fuel cell stack and the various losses and consumption of the power train devices. This model is then integrated into a global optimization algorithm, to determine the best race strategy to be adopted (velocity profile, motor current, gearbox ratio).

Le attività svolte dal CNR-ITAE per il progetto PON01_01366 "Nuovo processo a basso impatto ambientale ed a ridotto rischio operativo per il recupero ed il riciclo dei materiali costituenti le batterie al piombo" riportate in questo rapporto finale fanno parte dell'obiettivo realizzativo OR.3: "Costruzione di nuove batterie: analisi dei nuovi materiali e valutazione delle nuove tecnologie", e sono finalizzate alla realizzazione di elettrodi su piccola scala con i materiali rigenerati per lo studio delle proprietà elettrochimiche in cella singola. Per questo sono state determinate le capacità specifiche dei materiali indagati in diversi regimi di scarica, C20, C5 e 1C e le durate in prove di carica-scarica in cicli continui (Cycling). Inoltre sono stati studiati anche miscele di materiali ottenute mescolando il materiale rigenerato con materiale commerciale fresco. Misure di assorbimento di acido sono state anche eseguite sui materiali rigenerati. Tutti i risultati sono stati forniti a STC come pure le varie procedure di preparazione degli elettrodi allo scopo di dare un contributo alla messa a punto da parte di STC di un processo di produzione di elettrodi per batterie con i materiali riciclati.

Solid oxide fuel cells (SOFCs) are exposed to failures due to thermal and redox cycles, above all in the case of unexpected shut downs. Effects of thermal cycles related to controlled startup and shutdown can be mitigated by appropriate start/stop strategies, but unpredictable shutdowns strongly damage the devices, especially in anode supported cells. On the one hand, the nickel oxidation quickly arises above 250°C at the anode and usually leads to cells cracks; on the other hand, very fast cooling of the SOFC stack down to 250°C could lead to the thermal shock breakage as a consequence. Recently, reverse bias current application has been proposed to protect the anode from re-oxidation. In the presented work, the reverse bias current approach has been applied on a SOFC stack to assess the technique for relevant power devices. The results show that this protection method is promising as a safety approach.