Annual Symposium 2014

Tuesday 4 Nov 2014, 09:00 → 17:50 Europe/Zurich

Auditorium West WHGA001 (Paul Scherrer Institut)

The SCCER Storage

invites you to the first yearly symposium on heat and electricity storage.

This symposium provides the stage for informal exchange with experts in the field of:

· Battery Research
· Heat Storage
· Hydrogen Production and Storage
· Co - Electrolysis and CO₂ Reduction
· Interaction of Storage Systems

Both, academic researchers, as well as experts from industry are invited to this one- day symposium.
During the day, the relevant aspects from the industrial R&D sector, as well as the latest results from Swiss academic research is presented to equal parts for each of the  fields represented in the Competence Center for Heat and Electricity Storage.
The informal exchange is promoted by an extended poster session (please uplodad your poster abstract here) where the researches can present and discuss the results of  last years research.
This event is free of charge, but we ask you to Register

Slides

• SCCER_Hae_Symposium_2014_Abstracts.pdf
• Symposium_Flyer_final_web.pdf
• Symposium_Flyer_final_web.pdf
• Symposium_Flyer_final_web.pdf
• Symposium_Flyer_final_web.pdf
• Symposium_Flyer_final_web.pdf
• Symposium_SCCER_HaE.pdf

09:00 Registration and Coffee

1 Welcome and Introduction

Speaker: Thomas J. Schmidt (Paul Scherrer Institut)

Advance Batteries and Battery Materials

2 Advanced Electrode Materials for Li-ion and Na-ion batteries, and beyond

Speaker: Dr Maksym Kovalenko (Laboratory of Inorganic Chemistry EHTZ)

3 Batteries in the Challenge of Expectations and Realizations

Speaker: Dr Pascal Häring (Renata SA)

10:45 Coffee Break

Storage of Thermal Energy

4 Overview of SCCER Heat-Storage Research and Development Efforts

Following an outline of the motivation for heat storage in general and Switzerland in particular, the collaborators involved in the SCCER heat-storage research and development effort will be introduced. The objectives and current status of the projects on both low- and high-temperature heat storage will be described. Particular emphasis will be placed on explaining the relevance of the projects for the Energy Strategy 2050 and existing or potential industrial collaborations. The presentation will close with an outlook of future activities.

Speaker: Dr Andreas Haselbacher (Institute of Energy Technology, ETH Zürich)

5 Industrial Packed Bed of Rocks Thermal Energy Storage

Thermal energy storage (TES) systems enable dispatchability of concentrated solar power (CSP) plants and are therefore a crucial component in increasing the overall value of such plants. However, in commercially available CSP plants, typically using molten salt as TES, the cost of the TES system is about 10-15% of the total plant cost. Airlight Energy’s solar collector uses air as heat transfer fluid which enables the use of a simple yet effective TES system. The TES is based on a packed bed of rocks in a concrete container that is charged via direct heat exchange with air. Besides the drastically cheaper heat storage medium, the TES system eliminates the need for heat exchangers, typically necessary for molten salt TES systems, hence reducing significantly the overall TES costs. Consequently, the TES in an Airlight Energy CSP plant contributes to only about 1-2% of the overall plant cost. Several practical issues needed to be overcome for the realization of a reliable, industrial packed bed TES system. These challenges will be presented in the talk, together with the prototypes and industrial TES units built and tested so far. Fig. 1 and 2 show two of these units. Besides CSP applications, the cost effective and efficient nature of the packed bed of rocks TES makes it an attractive candidate for other applications requiring heat storage with air as heat transfer fluid, such as advanced adiabatic compressed air energy storage (AA-CAES). In an AA-CAES plant, the TES is used to store the heat created during the compression stage and later release it before the expansion stage. In this way, the efficiency of the plant can be significantly increased from typically 40% in conventional CAES plants, to above 70%. The TES is used in an AA-CAES test plant currently under construction in the Swiss Alps. Fig 1: A packed bed of rocks TES pilot unit in Biasca. Fig 2: A 100 MWhth TES for a CSP plant in Morocco

Speaker: Dr Gianluca Ambrosetti (Airlight Energy Holding SA, 6710 Biasca, Switzerland)

Meet and Eat, Poster session

Poster Session and Lunch

6 A Case Study in Power-to-Gas System Using Life Cycle Assessment

The future Swiss electricity supply system is expected to rely strongly on stochastic renewable generation such as photovoltaic and wind power. As a consequence, more and more flexibility is required and storage technologies will play a vital role in the integrated energy systems of the future. Under SCCER-Storage Work Package (WP) 5.1, integrated assessment for various storage technologies will be performed to better understand the impacts of these technologies in terms of environment, economy and their technology performance, and how they could be integrated into the overall energy system in the future. Life Cycle Assessment (LCA), as a key component in the technology assessment framework, has been applied to investigate the environmental impact of these technologies. In this poster, an example of how LCA is performed to assess the technology, and what results it could generate for decision makers’ reference has been presented over a case study on the power-to-gas system that is going to be built at Rapperswil Switzerland. The system is designed to convert electricity generated from renewable energy to hydrogen through electrolysis. The hydrogen generated is further reacted with carbon dioxide to produce methane, which will be dehydrated, compressed and eventually supplied to power cars. The work addresses LCA-implications of using methane from the power-to-gas system versus employing natural gas from conventional gas grid.

Speaker: Ms Xiaojin Zhang (Technology Assessment group, Paul Scherrer Institute, CH 5232 Villigen PSI)

7 A Kinetic Study of CO2 Electroreduction on Metallic Electrodes in Aprotic Media

Electrocatalytic conversion of CO2 into gaseous and liquid fuels has a great potential. However, significant conceptual and technological advances are still needed to make this process economically viable. Most studies on CO2 electroreduction were carried out using aqueous electrolytes. The solubility of CO2 in water is rather low, which leads to an undesirably low rate of mass transfer to the cathode. The use of non-aqueous electrolytes has the advantage of a significant increase in the CO2 solubility and allows avoiding intensive hydrogen evolution. In this work, we investigate electrocatalytic activity of Au, Pt, Cu electrodes as well as of Cu-modified Pt(hkl) single crystal electrodes in electroreduction of CO2 in aprotic solvents, such as acetonitrile and propylene carbonate [1]. We demonstrate that the CO2 reduction is a structure sensitive reaction under these conditions. Cu deposition increases the activity of Pt electrodes. The highest catalytic activity was found for compact Cu deposits on Pt(110) surface. The effect of addition of water on the kinetics and mechanism of CO2 reduction is also explored. Moderate amounts of water (≤ 1 M) in aprotic media leads to a drastic change in CO2 electroreduction kinetics. [1] Alexander V. Rudnev, Maria R. Ehrenburg, Elena B. Molodkina, Inna G. Botriakova, Alexey I. Danilov, Thomas Wandlowski, Electrocatalysis, 2014, DOI: 10.1007/s12678-014-0217-y

Speaker: Dr Alexander Rudnev (University of Bern)

8 A sectoral perspective on knowledge development and diffusion in the lithium-ion battery technology in the US and Japan

Lithium-ion battery technology is assumed to play an important role for future energy and transportation systems. Thus, industry, academia and policy makers aim at accelerating technological progress in this field. For the progress of a technology, knowledge development and diffusion plays an important role. Lithium-ion battery technology can be conceptualized as a complex product consisting of technically interrelated subsystems and components (multi-component technology). It is produced in different industry sectors that can be ordered along the battery supply chain. Organizations, mostly firms and research institutes, in these sectors share process-specific knowledge and capabilities required for the different components’ production, which differ strongly between the various sectors. Based on the multi-component multi-sector characteristic of the lithium-ion battery technology we specifically address the research question of which patterns of knowledge development and diffusion can be found across the different sectors of the lithium-ion battery technology. Knowledge is developed by different organizations and is transferred or recombined into new knowledge by the same or other organizations, which we refer to as knowledge diffusion. Hence, we focus on the two following aspects: First, to which extend do different sectors within the field of lithium-ion batteries specialize their knowledge within the sectoral boundaries with regard to their production activities or go beyond these boundaries (i.e. “which sector knows what”). Second, which patterns of knowledge flows can be observed within and across different sectors (i.e. “which sector learns from which sector about what”). We investigate the technology through a supply chain perspective enabling us to distinguish between different sectors and ensuring to encompass all relevant components. We employ a descriptive quantitative analysis of lithium-ion battery patent data in the period from 1985-2005 in the two most relevant countries, the US and Japan. Therefore, we assign each patent to (i) a component level and to (ii) a supply chain stage of the patent’s assignee. Our final database comprises 14,152 patents from Japan and 1,618 patents from the US. We take patent counts as proxy for knowledge development and counts of patents’ forward citations as proxy for knowledge diffusion and map knowledge development and diffusion regarding the two dimensions in both countries and over time. Our analysis shows that different sectors play different roles for the knowledge development and diffusion in the field of lithium-ion batteries. Especially firms of the sectors integrating lithium-ion batteries into larger technical systems (e.g. automotive, communication and IT technology) play the most decisive role for knowledge development and for knowledge diffusion. We furthermore show that knowledge development and diffusion started in specific component levels and from specific sectors and spread over time. Our results contribute to a better understanding of knowledge creation and learning mechanisms within the lithium-ion battery technology and provide a basis to derive sector-specific industry policy and management recommendations.

Speaker: Ms Annegret Stephan (ETH Zurich)

9 A uniform techno-economic and environmental assessment methodology for electrical and thermal storage development and integration in Switzerland.

The objective of this research (conducted in WP5 of SCCER-Storage) is to develop a uniform techno-economic and environmental assessment method for electrical and thermal storage. This assessment is intrinsically flexible because it can be applied to different energy storage (ES) technologies for both heat and electricity, for different applications and sectors. As shown in Figure 1, the analysis will integrate different levels including: • the storage unit, e.g. battery unit or hot water tank. • the application, e.g. renewable energy (RE) time-shift and demand shifting. • the system interactions, e.g. energy prices and reference scenarios. Within WP5, a time-dependant analysis will be conducted including RE intermittency, ES dynamics, energy prices with tariffs and demand load profiles. In first instance we focus on electricity, based on SWISSIX data; later on, we address district heating. This analysis will be compared with a time-independent approach based on pre-defined ES systems and constant energy prices in order to understand the impact of the temporal resolution on the results. The outputs of this assessment method will be used to quantify the benefits of ES for the Swiss energy system and the profitability for investors.

Speaker: Dr David Parra (Energy Group, Institute of Environmental Sciences, University of Geneva)

10 CATALYZED H SORPTION MECHANISM IN ALANATES

Bogdanovic [1] presented the Ti-catalyzed hydrogen sorption in NaAlH4. The mechanism of the catalysis remains unclear despite the large number of proposed models. We presented a completely symmetric mechanism where the catalyst had a well-defined function. Firstly, we focused exclusively on understanding the main intermediate steps in the dehydrogenation and rehydrogenation of MAlH4 and M3AlH6 (where M= Li, Na, and K) based on thermodynamic considerations. In this manner, the Gibbs free energy values of each possible step were calculated based on experimental determined thermodynamic data (enthalpies and entropies) of individual hydrides, MAlH4, M3AlH6, and MH. Secondly, the values for the activation energies, based on the intermediates MH and AlH3 were obtained. Lastly, we presented an atomistic model, where the catalyst acted as a bridge to transfer the M+ and H- from AlH4- to AlH63- and finally to form MH based on thermodynamic considerations. The proposed mechanism is symmetric and the catalyst is active on the intermediates NaH and AlH3 for the hydrogen de- and absorption. [1] B. Bogdanovic, M Schwickardi J. Alloys Compd., 253-254 (1997), pp. 1.

Speaker: Dr Zuleyha Ozlem Kocabas Atakli (Empa Materials Sciences and Technology, CH-8600 Dübendorf, Switzerland)

11 Compositional dependence of CuAu alloy nano-particles towards Electro-chemical reduction of CO2

The efficient conversion of CO2 into hydrocarbon fuels has attracted great attention in recent years. Our present work relates to the optimization of Cu:Au catalyst for the electro-reduction of CO2 in aqueous media. We synthesized various compositions of CuAu alloy nano-particles on vulcan carbon support by means of a single-step boro-hydride reduction process. The structure, composition and the electrochemical activity of these nano-particles with regard to the CO2 electro-reduction were studied by a combination of microscopic/spectroscopic methods (Transmission Electron Microscopy, Energy Dispersive X-ray analysis, X-ray Diffraction, X-ray Photoelectron Spectroscopy) and electrochemical (cyclic voltammetry, polarization, chronoamperometry) measurements. The catalytic activity of CuAu alloy compositions towards CO2 reduction is found to be strongly dependent on the particular Au content. The highest catalytic activity was observed for 65 at. % Au containing catalyst.

Speaker: Mr Motiar Rahaman (PhD Student)

12 Conversion of electricity into hydrogen using a dual-circuit redox flow battery

Redox flow batteries (RFBs) are very well suited for storing the intermittent excess supply of renewable electricity [1]. However, conventional RFBs cannot in many situations utilize all the available “junk” electricity due to a limited storage capacity, as they are charged and discharged electrochemically, with electricity stored as chemical energy in the electrolytes. In the RFB system reported here, the electrolytes are conventionally charged but are then chemically discharged over catalytic beds in separate external circuits. Recently we demonstrated a rapid chemical discharge of the battery chemically to produce hydrogen rapidly and efficiently [2]. The proposed system is able to generate hydrogen gas as secondary energy storage. For demonstration, indirect water electrolysis was performed with vanadium-cerium RFB, generating hydrogen and oxygen in separate catalytic reactions. The electrolyte containing V(II) was chemically discharged through proton reduction to hydrogen on a molybdenum carbide catalyst, whereas the electrolyte comprising Ce(IV) was similarly discharged in the oxidation of water to oxygen on a ruthenium dioxide catalyst. The dual-circuit RFB requires an efficient and low-cost catalyst for hydrogen evolution. We have recently demonstrated that molybdenum carbide (Mo2C) can be utilized to catalyze hydrogen evolution by an electrolyte containing vanadium(II), resulting in 100 % yield of hydrogen.2 Here we will present the latest results on the Mo2C catalyzed hydrogen evolution reaction, including an ongoing project to scale-up the hydrogen production process to the demonstrator level using a 10 kW dual-circuit all-vanadium redox flow battery. 1. B. Dunn, H. Kamath and J. M. Tarascon, Science, 2011, 334, 928–935. 2. V. Amstutz, K. E. Toghill, F. Powlesland, H. Vrubel, C. Comninellis, X. Hu, H. H. Girault, Energy Environ. Sci., 2014, 7, 2350-2358.

Speaker: Dr Pekka Peljo (EPFL)

13 Insights into d-band perovskite catalysts for application as oxygen electrodes in low temperature alkaline fuel cells and electrolyzers

Perovskites have recently shown the potentials of relatively high electrocatalytic activity towards oxygen reduction reaction (ORR)and oxygen evolution reaction (OER) in alkaline media.[1] Therefore they can represent potential low cost cathode and anode materials for low temperature alkaline fuel cell and electrolyzers, respectively. The basic perovskite oxide structure can be represented as ABO3, where A is the larger cation, such as a rare earth or an alkaline earth element, and B is the smaller cation, generally a transition metal. The ABO3 structure can accommodate cation substitution in a wide range by partial substitution of either the A and the B-site cation with another element giving (AxA`1-x)(ByB`1-y)O3 compositions. Such substitution leads to modification of the perovskite band structure which in turn modifies the electrical, optical and magnetic properties of the oxides, and, thus, may also have a significant effect on their electrocatalytic activity. Generally, the perovskite electronic properties are considered to be determined mostly by the B-site cation. When the B-site cation is a transition metal, the major contribution to the material physical properties derives from the B-site cation d-band electrons; for this reason perovskites having B-site transition metals are generally regarded as d-band perovskites. However, the A-site cation can also play an important role in the physicochemical properties of d-band perovskites. Its size determines whatever the crystal structure is deviated from the ideal cubic form and doping the A-site with an aliovalent element can lead to the formation of oxygen vacancies or electron holes. In the present work we have investigated the activity towards ORR and OER of Ba0.5Sr0.5Co0.2Fe0.8O3-d (BSCF)perovskite as single material electrode and as composite electrode coupling BSCF with functionalized acetylene black carbon. The rotating disk electrode (RDE) measurements showed that the composite electrode presents a lower overpotential towards both the ORR and the OER compared to BSCF and acetylene black single material electrodes, clearly pointing towards a synergistic effect between BSCF and acetylene black. X-ray absorption spectroscopy was used to unravel a possible electronic interaction between BSCF and acetylene black responsible for the superior electrochemical activity of the composite electrode.

Speaker: Dr Emiliana Fabbri (Paul Scherrer Institut)

14 Intercalation of hydrogen into Cu(111) under reactive conditions studied by in-situ STM

Dissociative adsorption and intercalation of hydrogen on/into metal surfaces is one of the most intensively studied processes in electro-catalysis. In our current study we present combined electrochemical and in-situ STM work on the impact of the hydrogen evolution reaction (HER) onto the structure of a Cu(111) electrode surface exposed to a dilute (5 mM) sulfuric acid solution (Fig. 1). Hydrogen evolution takes place at potentials more negative than the decay of the laterally ordered adlayer of sulfate anions. The adsorption/desorption and lateral ordering of sulfate is associated with the appearance of a pair of peaks in the respective voltammogram (P1 and P2 in Fig. 1). The reduction of hydronium cations into hydrogen strongly affects both the geometric and electronic structure of the Cu(111) surface without changing the overall atom density in the topmost copper layer. The latter effect has recently been described for the respective Cu(100) electrode surface under hydrogen evolution [1]. On Cu(111) a highly ordered (4 x 4) super-lattice forms under hydrogen evolution with an in-plane coordination of individual copper atoms that significantly deviates from an ideally hexagonal one. In-planes distortions and a profound buckling of the Cu(111) lattice is rationalized in the light of recent DFT calculations as a population and lateral ordering of sub-surface hydrogen [2]. [1] H. Matsushima, A. Taranovskyy, C. Haak, Y. Gruender, O. M. Magnussen, J. Am. Chem. Soc., 131, 10362 (2009). [2] M. F. Luo, G. R. Hu, Sur. Sci., 603, 1081 (2009).

Speaker: Mrs Thi Mien Trung Huynh (Department of Chemistry and Biochemistry, University of Bern)

15 Interfacial Electron Transfer between G. Sulfurreducens and a Gold Electrode: towards CO2 reduction studies

The discovery of electrogenic bacteria has been a big breakthrough in the research of new energy technologies paving the way for the development of microbial fuel cells (MFC) [1]. MFCs run without combustion and yield a higher efficiency as compared to combustion engines [2]. The bacteria of genus Geobacter sulfurreducens (Gs), which produce the highest current densities of known pure cultures, represent the most thoroughly investigated family of electrogenic bacteria [3]. Recently, Soussan et al. showed that Gs are capable to reduce CO2 [4]. In-situ spectroscopic investigations, such as the attenuated total reflection-surface enhanced infrared absorption spectroscopy (ATR-SEIRAS) and the gap-mode surface enhanced Raman spectroscopy (GM-SERS), provide clear evidences that outer membrane cytochromes (OMCs) in Gs are responsible for the direct electron transfer to the respective electrode during electricity production, and that OMCs slowly denature when they are in close contact with a bare gold electrode [5]. The introduction of self-assembled monolayers (SAMs) as a linker represents a promising approach that prevents the denaturation of OMC and acts, at the same time, as an electron transfer mediator between OMCs and the gold electrode [6]. In this presentation, we show the influence of the ω-terminal anchoring group of the linker molecules on the current production and immobilisation of Gs on SAM-modified electrodes. As a preliminary result, electrochemical studies showed that carboxylate-terminated linker SAMs immobilised Gs cells efficiently, while a chronoamperometric study showed only an 10% current production of Gs biofilm as compared to biofilms electrostatically attached on a bare gold electrode. An alternative strategy using silver nanoparticles formed and embedded within the Gs biofilms to enhance the electron transfer between Gs and the electrode is proposed. 1: D. R. Lovley, Annu. Rev. Microbiol. 2012, 66, 391-409. 2: C. Haynes, Journal of Power Sources 2001, 92, 199-203. 3: (a) D. R. Lovley, Curr. Opinion Biotech. 2008, 19, 564-571; (b) Energy Environ. Sci. 2011, 4, 4896-4906; (c) H. Yi et al., Biosens Bioelectron 2009, 24, 3498–3503. 4: L. Soussan, J. Riess, B. Erable, M.L. Delia, A. Bergel Electrochem. Commun. 2013, 28, 27-30. 5: A. Kuzume, M. Füeg et al. PCCP 2014, DOI: 10.1039/C4CP03357D 6: A. Kuzume, M. Füeg et al. Electrochim. Acta 2013, 112, 933-942.

Speaker: Mr Michael Füeg (University of Bern)

16 Layer-by-Layer Assembly of Ruthenium Complex Ultrathin Films for Electrochemical Pseudocapacitor Applications

The bottom–up assembly of functional nanoscale architectures from molecular components at the electrode surface has attracted much interest in the advancement of nano-technology and surface science. Particularly, the chemistry of surface modification by self-assembled monolayers (SAM) or by layer-by-layer (LbL) growth are highly promising approaches to construct two-dimensional (2D) and three-dimensional (3D) molecular systems on surfaces for various molecular electronics applications.1 Ultrathin films of Ruthenium complex were prepared on ITO surfaces by employing the LbL assembly. We demonstrate that these Ru complex thin films have a very well controlled thickness (few hundred nanometers, characterized by using AFM and Raman spectroscopy) and have relatively stable electrochemical redox characteristics (CV, galvanostatic charge-discharge, in-situ Raman spectroscopy), which are ideal characteristic features for thin film electrochemical pseudocapacitor applications.2 References: 1. M-A. Haga et al., Coordination Chemistry Reviews. 251 (2007) 2688–2701. 2. H. Dai et al., Journal of American Chemical Society, 132 (2010), 7472–7477.

Speaker: Dr Veerabhadrarao Kaliginedi (Department of chemistry and Biochemistry, University of Bern)

17 Metal free catalyst for chemoselective methylation of amines using CO2 as a carbon source

N-methylation of amines is an important step for pharmaceuticals and has been widely applied as key intermediates and important chemicals.1 Therefore, development of more efficient methylation methods continuously attracted the attention of chemists in the last decades. Still, the most common methylation of amines in industry makes use of toxic formaldehyde, whereas in organic synthesis less benign methylation reagents, for example, methyl iodide, and dimethyl sulfate, prevail. Thus, the application of more sustainable reagents is highly desired. In this respect, carbon dioxide is an attractive C1 building block in organic synthesis because it is an abundant, renewable carbon source and an environmentally friendly chemical reagent.2 Our main aim was to develop a metal free catalytic system which is having clear advantages of lack of sensitivity to moisture and oxygen, ready availability, low cost, and low toxicity, which confers a huge direct benefit in the production of pharmaceutical intermediates when compared with (transition) metal catalysts. Keeping these in our mind, we developed an active metal free catalytic system which works under mild reaction condition at atmospheric pressure (no need of autoclave) and at 50°C. This improved reaction condition is far better than the previous catalytic system known for this reaction and tolerated a wide variety of functional groups.3-5 This chemoselective nature of the catalyst is highly attractive for the ‘step-economy’ in a chemical synthesis of pharmaceuticals and fine chemicals.

Speaker: Dr Shoubhik Das (epfl)

18 MSn2 (M=Fe, Co, Mn) intermetallics as anode materials for Na-ion batteries

The need for higher specific energy batteries has led to the exploration of a range of conversion materials to be used as anodes in metal-ion batteries. Tin is one such promising novel anode material, which upon conversion to Li4.4Sn or Na3.75Sn has been found to show specific charge as high as 991 mAh/g and 846 mAh/g in lithium-ion and sodium-ion batteries, respectively [1, 2]. However, upon conversion this material experiences a volume expansion of up to 300 %, which leads to particle fracture and electrical isolation of particles with every cycle, resulting in fairly rapid capacity fade with cycle number. In an attempt to combat this volume expansion we alloyed the active tin with inactive transition metals to form the tetragonal intermetallic MSn2 (with M = Co, Fe, Mn), attempting to give the reaction a framework which buffer its expansions. The electrochemical behaviour of these alloys in Na-ion batteries was studied in a half-cell configuration and the mechanisms characterised using advanced electrochemical techniques as well as in situ and ex situ XRD analysis. Being isostructural, the only difference between these materials lies in the change of the transition metal. The three transition metals are known to be inactive towards sodium since Na-Co, Na-Fe and Na-Mn alloys do not exist, yet in spite of this the mechanisms by which the MSn2 alloy reacts within the battery depends strongly on what element tin is alloyed to initially. References: 1.Courtney, I.A., Journal of The Electrochemical Society, 1997. 44(6): p.2045. 2.Komaba, S., et al., Electrochemistry Communications, 2012. 21: p.65-68.

Speakers: Dr Claire Villevieille (Paul Scherrer Institut), Ms Leonie Vogt (Paul Scherrer Institut)

19 Nano-LiCoO2: organometallic precursors as source of high Li-ion diffusion oxides for battery purpose.

High-temperature lithium cobalt oxide (HT-LiCoO2) and its multimetallic derivatives containing nickel, manganese and aluminum (LiNi0.33Co0.33Mn0.33O2 and LiNi0.8Co0.15Al0.05O2) are currently the most used cathode materials for secondary lithium ion batteries (LIB). Its industrial synthesis requires rather long and high energy consuming heat treatments.[1] Those processes generally produce particles in the micrometric range with a relatively large disparity of size and shape. In order to decrease the necessary time, the energy and by extension the manufacturing cost and ecological impact of this cathode material, a new organometallic way for the formation of lithium cobalt oxide has been investigated. This method is based on the formation and the combustion of pre-organized complexes using O-donor ligands such as aryloxides and alkoxides. The amount of carbon per ligand has been reduced to one with the methoxide as ligand. Several different precursors have been successfully synthesized. The total time of preparation has been reduced to 3 h and the temperature required has been lowered to 450 °C.[2] The size of the particles could be tuned down to nanoscopic scale. Finally, the nano-LCO showed an interesting enhancement in terms of Li-ion diffusion, which is one of the key parameters in LIB. [1] “Atomic resolution of lithium ions in LiCoO2”, S.-H. Yang, L. Croguennec , C. Delmas, E. C. Nelson, & M. A. O'Keefe, Nat. Mater., 2003, 2, 464-467. [2] “Lithium metal aryloxide clusters as starting products for oxide materials”, A. Crochet, J-P. Brog & K. M. Fromm, 2012, Patent, N° WO 2012000123

Speaker: Mr Jean-Pierre Brog (University of Fribourg)

20 Particle size and shape dependence of the ionic diffusivity in LiMnPO4 cathode for lithium ion batteries

Advanced lithium ion batteries require higher safety, lower cost, longer durability and lower toxicity to apply larger applications [1]. LiMnPO4 can be an alternative cathode material due to its stable structure, low material cost, lower toxicity, high theoretical capacity (170 mAh/g), high operating voltage (4.1 V vs. Li) and good capacity retention. However, it suffers from poor electronic and ionic conductivity [2, 3]. Its poor ionic conductivity can be overcome by employing nano-particles in order to shorten Li-ion path lengths [4, 5]. Enhancement in electron transport is achieved by carbon coated nanocomposite cathode material [6, 7]. Most high-performing LiMnPO4 materials were so far achieved by adding a large amount of carbon (15 – 30 wt%) in order to increase the electronic conductivity [8,9]. Recently, we reported < 30 nm sized nano-LiMnPO4 reached 97 % of theoretical capacity with 10 wt% of carbon additive in total in the electrodes [10]. We investigated further to study the favorable direction for lithium ions in different shapes of nano-LiMnPO4 and the desired composite structure to improve the electrochemical properties. Since olivine LiMnPO4 materials have one preferred direction of lithium ion diffusion in the lattice, we synthesized various shapes and sizes of nano-LiMnPO4 (Fig. 1). Chemically exfoliated graphene from graphite flake was applied to nano-LiMnPO4, forming a thin coating on the surface of the active material (Fig. 2). Afterwards, we determined the lithium ion diffusion coefficients in terms of shapes and sizes of LiMnPO4 nanomaterials using an electrochemical technique of cyclic voltammetry (Table. 1).

Speakers: Prof. Katharina Fromm (University of Fribourg, Chemistry department), Dr Nam Hee Kwon (University of Fribourg, Chemistry department, Fribourg, Switzerland)

21 Phase change material systems for high temperature heat storage

The development of technologies for energy storage has been intensified in recent years driven by the disparity between energy availability and demand, which is expected to increase further as an increasing amount of energy is provided from renewable and intermittent sources. A large fraction of the end energy is used in heating applications, in Switzerland amounting to about 50% of which an estimated 14% is used in high temperature applications (temperatures >400°C). In order to cover this need for continuous availability of thermal energy with renewable sources or waste heat, advanced heat storage technologies are required. Latent heat storage by means of phase change materials (PCM) has proven to be an attractive heat storage technology. Key advantages include the high energy storage density, applicability to high temperatures, and the ability to store and release heat at a constant temperature. We developed a 1D numerical model of a basic latent heat storage material system composed of a metallic PCM and a metal-ceramic PCM encapsulation. Using a metallic PCM with high material bulk conductivity compared to materials commonly used as PCMs, such as salts, automatically alleviates challenges connected to inefficient charging and discharging. The multi-component encapsulation allows for robustness via the chemically inert and thermally stable ceramic layer while ensuring mechanical stability and enhanced heat transfer by the metallic layer. During charging a heat transfer fluid (HTF) at high temperatures (above the melting temperature of the PCM) transfers its thermal energy to the PCM by convective, conductive, and radiative heat transfer. During discharging, the HTF is below the melting temperature of the PCM and heat is transferred back, thus the heated HTF can be used in subsequent thermal applications such as power generation or process heat. The model is used to select suitable PCM material systems and operating conditions based on a variety of up and downstream applications. Subsequently, full three dimensional models including all relevant physical phenomena such as convection, conduction, radiation and phase change will be developed, to investigate the charging and discharging, and to optimize the performance. Detailed simulations will support the design and implementation of well performing high temperature heat storage systems. Such systems will contribute to an energy economy with an increased fraction of renewable energy sources and will be able to smoothen fluctuations in the incoming energy sources, thus solving two issues of paramount importance in the context of renewable energy.

Speaker: Mr David Perraudin (EPFL)

22 POLYANIONIC CATHODE MATERIALS FOR SODIUM ION BATTERIES

Sodium ion batteries are emerging to be future energy storage devices replacing its counterpart lithium ion batteries owing to its limited geographical constraint and thereby restricting to meet the global demands. Polyanion (PO43-, P2O74-) based cathode materials for sodium ion batteries are better candidates on grounds of cycle stability, thermal stability, safety, environmental friendliness and cost.

Speaker: Mr Sivarajakumar Maharajan (University of Fribourg)

23 Power-to-Gas

see poster

Speaker: Dr Markus Friedl (Institut für Energietechnik)

24 Sn anode for Na-ion batteries: A bulk and interfacial study

The development of Na-ion batteries is one of the most promising challenges of the decade. Although the fundamental principles of sodium based batteries are by principle identical to the lithium ones, the number of materials to be investigated is three times more than lithium according to the ICSD (inorganic crystallographic structure database) database. Therefore, unexplored reaction mechanisms are expected in Na-based systems, which should be investigated and understood to warrant further development. In the literature, some groups reported impressive specific charges above 400mAh/g and unexpected columbic efficiencies beyond 90% for materials with more than 200% volume change such as Sn, Sb or intermetallic alloys Cu2Sb, SnSb. Most of these researches used the same electrolyte, 1M NaClO4 dissolved in propylene carbonate (PC) with or without fluroethylene carbonate (FEC) used as additive. The FEC additive is reported to be of great importance to maintain the specific charge above 400mAh/g and to help to sustain the coulombic efficiency during more than 100 cycles in intermetallic electrodes. We will analyse here the properties of the Sn bulk by operando XRD and the interface layer (SEI) after cycles will be characterized by post mortem SEM, XPS.

Speaker: Dr Claire Villevieille (Paul Scherrer Institute)

25 Study of the oxygen evolution mechanism and activity of Perovskite La1-xSrxCoO3-based electrodes in alkaline media by thin film rotating ring disk electrode measurements

Fuel cell and electrolyzers can represent a mid-term solution to the present need for a sustainable energy economy; they can be combined with renewable energy resources to build up a novel and sustainable energy based on power grids. One of the main drawbacks which hinders low temperature fuel cells and electrolyzers commercialization is the high costs of these devices. A considerable decrease in their cost can be achieved by developing non-noble metal electrocatalysts which are able to provide high catalytic activity towards the oxygen reduction and evolution reaction (fuel cell and electrolyzer mode, respectively). Particularly, perovskite oxides have recently shown the potentials of high electrocatalytic activity towards oxygen evolution reaction (OER) [1] and oxygen reduction reaction (ORR) [2-3] in alkaline media. The basic perovskite oxide structure can be represented as ABO3, where A is the larger cation, such as a lanthanide or an alkaline earth element, and B is the smaller cation, generally a transition metal. The ABO3 structure can accommodate cation substitution in a wide range by partial substitution of either the A and the B cation with another element giving (AxA`1-x)(ByB`1-y)O3 compositions. Even though the A-site ion does not really contribute to the electronic conduction, its size and valence were found to be important factors controlling the perovskite crystal structure and as a consequence also the electronic properties. A particular interesting case is La1-xSrxCoO3; at low values of x these oxides are p-type semiconductors while x>0.2 the conductivity changes in semi-metallic or metallic type [4]. In the present work we have investigated the OER/ORR mechanism and activity of single and composite electrodes based on La1-xSrxCoO3 (x=0, 0.2, 0.6, 1) perovskite by thin film rotating ring disk electrode (RRDE) technique. La1-xSrxCoO3 powders were synthesized using a modified sol gel process, starting from an aqueous solution containing La, Sr and Co nitrate precursors. Citric acid and nitric acid were added to the nitrate solution as a complexing agent and oxidant additive, respectively. The solution was then heated under stirring to evaporate water until it changed into a viscous gel and finally ignited to flame, resulting in a black ash. To obtain single phase material, the La1-xSrxCoO3 powder was calcined at 1000 °C for 2 h in air. The specific surface of the oxide catalysts was determined by Brunauer-Emmett-Teller (BET) analysis. Most of the perovskite oxides show low surface area, since their synthesis requires relatively high calcination temperatures. Furthermore, they possess relative low conductivity and for this reason carbon is often added to the perovskite electrode to eliminate any possible concern about their electrical conductivity. However, carbon is known to possess a significant activity towards ORR in alkaline media reducing O2 to peroxide via a two electron process [5]. Differently, in the typical oxygen evolution potential range carbon is expected to be strongly oxidized. Therefore, the influence of carbon addition to perovskite catalysts on the ORR and the OER should be systematically studied. For the electrochemical characterization, thin films were prepared by drop-coating a cathode ink on glassy carbon disks. The cathode inks were prepared from a suspension made of La1-xSrxCoO3, Na+-exchanged Nafion solution, and acetylene black (Alfa Aesar) in isopropanol. RRDE measurements were performed at room temperature in 0.1M KOH electrolyte, applying different rotation speeds and with a scan rate of 5 mVs-1. A new method was also applied to investigate the chemical/electrochemical activity of La1-xSrxCoO3 perovskite towards peroxide decomposition [6].

Speaker: Dr Xi CHENG (PSI)

26 Synthesis of SnO2 nano particles on PVP functionalized reduced graphene oxide by self-capping function of hexanoate ligands: An application for electrochemical CO2 reduction in aqueous medium

Synthesis of SnO2 nano particles on PVP functionalized reduced graphene oxide by self-capping function of hexanoate ligands: An application for electrochemical CO2 reduction in aqueous medium Abhijit Dutta, Motiar Rahaman,Thomas Wandlowski, Peter Broekmann Department of Chemistry and Bio-chemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland Abstract: The increase of carbon dioxide (CO2) in the atmosphere is asserted to be one of the major suppliers to the greenhouse effect. The electro-catalytic reduction of CO2 to liquid fuels is a critical goal that would positively impact the global carbon balance by recycling CO2 into usable fuels. To address this challenging scientific problem, we need to advance our fundamental understanding of the chemistry of CO2 activation and develop novel multifunctional catalysts that could use electricity to efficiently break C-O bond and form C-H and C-C bonds. An appropriate energy input and reasonable productivity of fuels are also important considerations for practical industrial processes. There are many heterogeneous catalytic processes in energy conversion and storage systems possess necessary surface active sites of the catalysts matrix in an efficient way. Here, we synthesized SnO2 nano particles having 5–8 nm in size on polyvinylpyrrolidone (PVP) functionalized reduced graphene oxide via a non-hydrolytic solvothermal reaction with hexanoate complexes. PVP is used to stabilize graphene sheets in solution and prevent their aggregation. The dissociated hexanoates ligand on the metals, working as a capping agent, induces the size control of the nano-particles during the synthesis. The synthesized nanoparticles are soluble in a non-polar solvent and can also be form a transparent suspension in an aqueous solution by converting the capping group to a citrate. The surface morphology of the catalysts is determined by XRD (X-ray diffraction), TEM (transmission electron microscopy) and XPS (X-ray photoelectron spectroscopy) analysis. XRD patterns reveal that all the catalysts have disordered cassiterite in structures. Low resolution TEM images reveal uniform dispersion of SnO2 nano particles on reduced graphene nano sheet having an average size of 5-8 nm. The X-ray photoelectron spectroscopy revel the charge density redistribution via the nano-scale formation of SnO2 nano-particles and rGO which is paramount to import surface active sites. The composite materials are electrochemically characterized by cyclic-voltammetry (CV), linear sweep voltammetry (LSV), and chronoamperometry (CA) in CO2 saturated 0.5M NaHCO3 medium. Reference: 1. W. Li, et. al, ACS Symposium Series, Chapter 5, pp 55–762. 2. J. Qiao et.al. . Chem. Soc. Rev. 00, (2013) 1 3. A. Dutta, et.al, Applied Catalysis B, 158–159 (2014) 119–128

Speaker: Dr Abhijit Dutta (Department of Chemistry and Bio-chemistry, University of Bern)

27 Thermo-mechanical characterization of cellular ceramics in high-temperature environments

Cellular ceramics are attracting materials for high temperature applications such as high-temperature thermal storage systems, thermal protection systems, burners, reformers, and solar radiation absorbers. These material structures are able to withstand oxidative environments at high temperatures and are particularly resistant to thermal shock. As typical for ceramic materials, thermal stresses are one of the major reasons of failure in these components when used in high temperature applications. The study of this phenomena is a difficult task since it couples the thermal physics and structural mechanics of ceramics with a possibly complex cellular structure. X-ray computed tomography of a commercially available SiSiC foam produced by the replica method, was used to digitally reconstruct the cellular structure. We then used the finite element method (FEM) as well as experiments to study the effect of structural features on ceramic foams’ mechanical and thermal properties. In a second step, models of lattice structures made of ordered tetrakaidecahedral unit cells – a unit cell often used to represent the microstructure of commercial foams – were simulated and their morphology (e.g. strut shape, cross section, and thickness) optimized for enhanced thermo-mechanical properties. Optimized structures made of SiSiC were produced using advanced additive manufacturing techniques in conjunction with the conventional replica method. Their mechanical properties were then tested using non-destructive techniques (acoustical emission and electrical resistance) and compared to the FEM numerical modeling. Lattice structures showed to have a more predictable behavior than the commercial, random structures but highly dependent on the unit cell structure and arrangement. The method allows to determine the factors influencing the behavior of the cellular ceramics under both thermal and mechanical load and subsequently allow to optimize the structures for enhanced performance.

Speaker: Mr Ehsan Rezaei (EPFL)

Hydrogen Production and Storage

28 Advances in Hydrogen Production and Storage

The storage of renewable energy is the greatest challange for the transition from the fossil aera to a sustainable future energy economy. Hydrogen produced from renewable energy leads to a closed cycle, because the water relesed from the combustion condenses in the atmosphere. The challange in the large scale application of H2 is the storage with a high gravimetric and volumetric density. based on todays knowledge a hydrogen storage is limited to about 20 mass% and 70 kg/m3. Moreover the afforable and sustainable production of hydrogen using renewable energy faces challenges in off-grid and small-scale (distributed) application. The work package "Hydrogen Production and Storage" of the SCCER "Heat & Electricity Storage" focuses on the following topics: 1) Hydrogen production by chemical discharge of a reversible flow battery (RFB) [1] Conventional RFBs are charged and discharged electrochemically, with electricity stored as chemical energy in the electrolytes. In the RFB system reported here, the electrolytes are conventionally charged but are then chemically discharged over catalytic beds in separate external circuits. The catalytic reaction of particular interest generates H2. Indirect water electrolysis was performed generating hydrogen and oxygen in separated catalytic reactions. The electrolyte containing V(II) was chemically discharged through proton reduction to H2 on a molybdenum carbide catalyst, whereas the electrolyte comprising Ce(IV) was similarly discharged in the oxidation of H2O to O2 on a RuO2 catalyst. This approach is designed to complement electrochemical energy storage and may circumvent the low energy density of RFBs especially as hydrogen can be produced continuously whilst the RFB is charging. 2) Sustainable Electrocatalysts for Hydrogen production using renewable energy [2] A challenge in the production of Hydrogen from renewable energy using water electolysis at low current density (ca. 10 mA cm–2 is the identification of inexpensive and scaleable catalysts materials to reduce the overpotential required to drive the water oxidation and reduction reactions. While Platinium is traditionally used for the water rediction half-reaction, it is not scalable to the terawatt range necessary. Abundant transition metal compunds (e.g. MoS2) have been identified as promising replacments for Pt in this appication. We have recently developed a novel way to solution process natural (bulk) MoS2 into thin film electrodes. [2] Subsequently we have demonstrated that these electodes have high activity for water reduction at low overpotential (0.2 V at 10 mA cm–2) even with only a few atomic layers of (solution-processed) MoS2. 3) Hydrogen storage in hydrides [3] Bogdanovic [4] presented at MH1996 the Ti-catalyzed hydrogen sorption in NaAlH4. The mechanism of the catalysis remains unclear despite the large number of proposed models. We developed an atomistic model, where the catalyst acts as a bridge to transfer the Na+ and H- from AlH4- to AlH63- and finally to form NaH based on thermodynamic considerations. The proposed mechanism is symmetric and the catalyst is active on the intermediates NaH and AlH3 for the hydrogen de- and absorption. 4) Hydrogen storage in formic acid [5] Hydrogen as an energy vector could be a solution for transport/mobile applications, based on its high energy content and the high efficiency with which its chemical energy can be transformed into electricity in state-of-the-art fuel cells. Classical hydrogen storage methods suffer from weight, cost and safety issues. Chemical hydrogen storage has found considerable attention and formic acid is among the most promising compounds to achieve it. Formic acid has a high volumetric hydrogen content, favorable physical properties and is simple to use, ideal for both mobile and stationary applications. Also, a hydrogen/energy storage-and-release cycle based on formic acid decomposition and carbon dioxide hydrogenation can be envisioned that could solve the inflexibility of decentralized power generation. References [1] V. Amstutz, K. E. Toghill, F. Powlesland, H. Vrubel, C. Comninellis, X. Hu and H. H. Girault, "Renewable hydrogen generation from a dual-circuit redox flow battery", Energy & Environmental Science 7 (2014), p. 2350 - 2358. [2] X. Yu, M. S. Prévot, K. Sivula, “Multiflake Thin Film Electronic Devices of Solution Processed 2D MoS2 Enabled by Sonopolymer Assisted Exfoliation and Surface Modification” Chem. Mater. (2014), ASAP doi: 10.1021/cm502378g. [3] Z. Ö. Kocabas Atakli, E. Callini, S. Kato, A. Züttel, "Catalyzed H Sorption Mechanism in Alanates", to be submitted to J. Alloys and Compounds (2014). [4] B. Bogdanovic, M. Schwickardi, “Ti-doped alkali metal aluminium hydrides as potential novel reversible hydrogen storage materials”, J. of Alloys and Compounds 253, 1-9 (1997). and B. Bogdanovic et al., J. Alloys and Comp. 302 (2000), pp. 36 - 58 [5] S. Moret, P. J. Dyson, G. Laurenczy, “Direct Synthesis of Formic Acid from Carbon Dioxide by Hydrogenation in Acidic Media”, Nature Communications 5 (2014), 4017

Speaker: Prof. Andreas Züttel (Ecole polytechnique fédérale de Lausanne (EPFL), Institut des sciences et ingénierie chimiques, CH-1015 Lausanne, Switzerland, EMPA Materials Science & Technology, Div. Hydrogen & Energy, Dübendorf, Switzerland)

29 Megawatt Scale PEM Electrolysis for Energy Storage Applications

As the percentage of the traditional electrical grid power supplied by renewable sources such as wind and solar energy grows, energy storage solutions are required in order to maintain stable grid performance. These solutions have to provide both generation capacity for periods of low renewable generation or peak demand, and storage capacity for peak periods such as high wind periods and mid-day with low cloud cover. Specific areas of the world such as Germany and California are already requiring energy storage as part of new renewable installations based on these issues. Hydrogen from electrolysis is a promising technology for all of the above applications, also providing potential linkages between other infrastructures such as transportation to provide flexibility in the overall solution. Hydrogen has the capability to store massive amounts of energy in a relatively small volume, with no carbon footprint when generated from electrolysis of water and renewable energy. Electrolysis can also provide ancillary services (e.g., load shifting and frequency regulation) for grid stability, resulting in multiple value streams. The hydrogen produced can be injected into the natural gas pipeline, in the production of high value chemicals such as ammonia, in upgrading of biogas, or used as a transportation fuel. Europe in particular has been committed to these pathways and making heavy investment in both materials research and system design and development as well as technology demonstration. In Germany, hydrogen is looked upon as a key part of the energy storage solution under “Energiewende,” their national sustainable energy transition plan. Hydrogen provides a unique link between the electric and gas grid infrastructures (often referred to as “PtG= Power-to-Gas”). Proton exchange membrane (PEM) electrolysis is attractive for hydrogen generation applications because of the lack of corrosive electrolytes, small footprint, and ability to generate at high hydrogen pressure, requiring only water and an energy source. The major market challenge for PEM competing directly with traditional liquid alkaline electrolysis technology has been product scale. However, that obstacle is decreasing as PEM-based products have increased in output. Several companies have already announced development plans for commercial megawatt (MW)-scale PEM electrolysis units in the 2014-2015 timeframe and there have been recent announcements of large scale renewable energy storage projects based on electrolysis. This presentation will provide information about Proton OnSite’s PEM electrolysis plants installed in Europe by Diamond Lite as a system integrator for different applications, and PtG projects in Switzerland to be completed by end of 2014. Information will be presented on Proton OnSite’s MW product development effort, including a new large format PEM stack that achieves substantial cost reduction. These reductions were achieved through research in bipolar plates and the membrane electrode assembly, and additional improvements are possible based on Proton’s ongoing projects, which will be discussed. Endurance and variable load testing will be presented.

Speaker: Mr Marc Uffer (Diamond Lite SA)

Catalytitc and Electrocatalytic CO₂ Reduction

30 Catalytic and Electrocatalytic CO2 Reduction: the Genesis of Working Group 4 in the SCCER Heat & Electricity Storage

In this presentation the research groups participating in the working group ‘Catalytic and Electrocatalytic CO2 Reduction’ will be introduced with an emphasis on previous relevant research on CO2 chemistry. The expertise and unique research tools that will be shared between the research groups will be highlighted. Collaborations with other groups on CO2 chemistry that could contribute towards the success of the working group will also mentioned. Also, the synergies and parallels between the materials being developed for applications in the electrocatalytic conversion of CO2 into fuels and the homogeneous/heterogeneous catalysts for CO2 hydrogenation will be made. Finally some highlights of very recent research successes on the transformation of CO2 into chemicals and fuels will be given.

Speaker: Prof. Paul Joseph Dyson (EPFL ISIC LCOM)

31 Power-to-Value Concepts for Storage of Renewable Energy

The enlargement of the feed-in capacity of volatile renewable electricity into the grid implies the necessity to convert this energy into storable materials during times, where the excess of energy cannot be consumed by the net. The Power-To-Gas or SolarFuel concept stores the excess energy in i.e. methane, which could be eventually back converted into electricity on demand. Such seasonal, large scale concepts are very reasonable from the energetic and ecological point of view. However, it is very hard to obtain economic feasibility when considering the low fossil energy carrier prices and the physical efficiency limitations of the processes. Power-to-Value targets to maximize the ecological and economical benefit with respect to the available excess energy. Therefore its scaling is limited only by the stage of expansion of the absolute amount and proportion of solar and/or wind energy in the grid mix. Power-to-Value unifies energy storage, emission reduction, chemical feedstock and economic feasibility. The price of most chemical compounds is much higher when compared to its energy content. In the presentation, two potential approaches are discussed. 1. Direct electrochemical reduction of CO2 towards chemical feedstock The current emission of CO2 from power plants is an almost inexhaustible carbon source. Depending on the electro catalytic system, CO2 can be electrochemically reduced to carbon monoxide (CO), methane (CH4), ethylene (C2H4) and various other hydrocarbons even in aqueous media. CO and C2H4 are valuable feedstock for the chemical industry with a coincident high yearly sales volume. CO could be obtained with faradic efficiencies over 90% at current densities exceeding the industrial necessary level of 100 mA/cm² with a total energy efficiency approaching 50%. Ethylene is more challenging due the highly complex reduction process involving 12 electrons and 8 protons. Faradic efficiencies up to 40% for ethylene could be obtained using structured copper based electrodes. 2. Energy storage and discharge using alkaline or earth alkaline metals (Earth) alkaline metals are intrinsically high density energy storage materials due to their electrochemical potential. The production of these metals is well established using electrolysis and could, therefore be quickly scaled up. The question arises, how to discharge this energy carrier delivering energy and simultaneously producing high value chemicals. (Earth) alkaline metals can even be burned in atmospheres such as CO2, H2O and N2 yielding products such as CO, H2 or nitrides. The temperature of the combustion is high enough to drive ordinary steam power plants. The nitrides can exothermally be hydrolyzed to the fertilizer ammonia (NH3). We have built a 30 kW burner, which burns molten Lithium in the various atmospheres. The presence of all desired products could be confirmed by chemical analysis.

Speaker: Dr Guenter Schmid (Siemens AG, CT NTF COS)

15:15 Coffee Break

Technological Interaction of Storage Systems

32 Technology Interaction of Storage Systems - Gaining Flexibility between the Energy Grids

TBD

Speaker: Prof. Jörg Worlitschek (Hochschule Luzern - Technik & Architektur)

33 The "Hybridwerk Aarmatt"

Künftig soll der grösste Teil unserer Energie aus regenerativen Quellen stammen. So wollen es die politischen Kräfte in Bundesbern. Auch wenn um die Höhe und das Tempo noch gerungen wird, ist eines sicher: es kommen grosse Herausforderungen auf die Energiebranche zu. Vor diesem Hintergrund hat die Regio Energie Solothurn unter dem Namen „Hybridwerk“ ein innovatives Projekt in Angriff genommen. Auf dem Areal Aarmatt verfügt die Regio Energie Solothurn über eine ideale Ausgangslage zur Realisierung dieses Projektes. Die drei Energienetze Strom, Gas und Fernwärme kommen auf diesem Areal zusammen. Das jüngste Netz in der Infrastruktur der Regio Energie Solothurn ist das Fernwärmenetz. Es war ursprünglich der Auslöser für das Projekt. Eine der Herausforderungen, welche durch die Energiewende ausgelöst werden, ist der Umgang mit grossen und stark schwankenden Mengen und Leistungen insbesondere von Photovoltaik-Strom. Alle Szenarien gehen heute davon aus, dass die Photovoltaik in der Schweiz den grössten Anteil an den neuen Erneuerbaren ausmachen wird. Sauber, unerschöpflich, technisch ausgereift, so stellt sich die Photovoltaik heute dar. Einziges „Manko“: PV-Strom fällt höchst unregelmässig an und ist schlecht prognostizierbar. Unregelmässig heisst, viel im Sommer, wenig im Winter. Aber auch viel am Tag, nichts in der Nacht. Für den Ausgleich und die Stabilität des Stromnetzes braucht es in der Zukunft vermehrt Speicher. Es stellt sich die Frage, welche Speicher dafür geeignet sind. Die Regio Energie Solothurn setzt auf Erdgas als Speichermedium. Somit sprechen wir über Power to Gas. Das Herzstück der Anlage bildet der Elektrolyseur, der Strom in Wasserstoff umwandelt. Der Wasserstoff kann methanisiert oder direkt dem Gasnetz zugeführt werden. Die Stromüberproduktion wird also in speicherbares Gas umgewandelt. Die Netze Fernwärme, Erdgas und Strom werden über den Elektrolyseur und die anderen Komponenten des Hybridwerks miteinander verbunden. Das Hybridwerk kann Energien umwandeln, speichern und bei Bedarf in der gewünschten Form (Strom, Gas, Wärme) zur Verfügung stellen. Das Hybridwerk der Regio Energie Solothurn löst zwar nicht alle energiewirtschaftlichen Herausforderungen, die mit der Energiewende auf die Branche. Das Hybridwerk wird indessen wertvolle Impulse und Erfahrungen liefern, was mit modernster Technologie und unternehmerischem Denken bereits heute möglich ist....und wo die Grenzen liegen.

Speaker: Mr Marcel Rindlisbacher (Regio Energie Solothurn)

34 Socio-economic energy research and its potential relevance for storage

TBD

Speaker: Prof. Frank Krysiak (Department of Business and Economics University of Basel)

35 Wrap-Up

Speaker: Thomas J. Schmidt (Paul Scherrer Institut)