The FestBatt competence cluster includes eight joint projects in a total of seven platforms. The platforms are supported by a coordination project with the common goal of building up expertise in solid-state batteries and solid electrolytes and their characterization.
Cell Platform Oxides
Ceramic solid electrolytes based on the oxide class offer high oxidation stability and are therefore attractive as materials for cathode composites and as direct coatings of cathode active materials. Electrolyte materials based on Li7La3Zr2O12 (LLZO) are one of the few material groups that are practically reduction-stable against lithium metal anodes. In addition to the production and optimization of oxide electrolyte materials, the focus of the platform is on the processing of cathode composites with oxide catholytes through to innovative full-cell concepts. The objectives are focused on further development of all necessary materials and processes for the successful demonstration of oxide ceramic cells as well as hybrid cell concepts with oxide components. This platform also aims to overcome the challenges of co-sintering of cathode and solid electrolyte in oxide ceramic process technology, for example by developing mixed cathodes using powder aerosol deposition (PAD) to avoid the formation of harmful interdiffusion layers at elevated temperatures.
Platform Coordinator: Prof. O. Guillon
Forschungszentrum Jülich GmbH
Institute of Energy and Climate Research – Materials Synthesis and Processing (IEK-1)
Wilhelm-Johnen-Straße , 52425 Jülich
Cell Platform Polymers
In this platform, polymer electrolyte-based battery cell concepts are developed, optimized, and expanded, particularly to improve fast-charging capability and lower the operating temperature. Hereby, the consortium focuses on concepts with lithium metal anodes, Ni-rich NCM cathodes, hybrid cells and those with "quasi-solid" polymer electrolytes. This research aims to realize efficient, safe, cost-effective, and environmentally friendly battery technologies. The application-oriented development of pouch cells without external pressure thus plays a central role in achieving high energy densities in the battery pack. The consortium especially aims to design functional layers, develop concepts for electrode structuring, optimize relevant processing conditions, scale polymer syntheses, manufacture composite cathodes, and develop competence for defect mechanisms and charge transfer processes within the cells. The development of cell concepts and the necessary material combinations is accelerated in close cooperation with the method platforms.
Platform Coordinator: Prof. M. Winter
Forschungszentrum Jülich GmbH
Institute of Energy and Climate Research, Helmholtz Institute Münster (HI MS): Ionics in Energy Storage (IEK-12)
Corrensstr. 46, 48149 Münster
Cell Platform Thiophosphates
The central goal of this project is the development and successful realization of high-performance solid-state batteries based on thiophosphate solid electrolytes. This requires material- and process-based optimization and adaptation of all cell components (electrodes, solid electrolytes, separators) and full cells. To this end, the consortium covers the entire research and production chain: On the one hand, this includes the chemical optimization of thiophosphate solid electrolytes, such as those based on Li6PS5Cl (LPSCl) and Li7SiPS8 (LiSiPS), and the scaling of electrolyte syntheses. On the other hand, the platform addresses the improvement of electrodes with high specific capacity and rate capability, the preparation of separators that are as thin as possible and the assembly of full cells with high energy and power density with a long cycle life and minimal capacity loss. To establish competitive battery cells, the consortium also evaluates concepts with lithium metal and silicon-based anodes, as well as the thermal safety of solid-state battery cells based on thiophosphates.
Cross-Sectional Platform Hybridization
This cross-sectional platform investigates and develops hybrid cell concepts and hybrid electrolytes to combine the advantages of different electrolyte classes and cell concepts. Here, the consortium particularly focuses on concepts with lithium metal anodes and Ni-rich NCM cathodes to establish fast-charging cells. This requires innovative strategies and sophisticated cell designs. Particularly, methods for processing hybrid separators and producing composite cathodes are being developed, especially with regard to reversibility and rate capability. The solid hybrid separators are developed from combinations of polymers with oxides and polymers with thiophosphates and the processing conditions of adapted solid electrolytes are optimized. The aim is to enable controlled, safe, and reversible energy storage in solid-state batteries with a long service life. This development of different cell concepts and material combinations is carried out in close collaboration with the cell platforms and is accelerated by cooperation with the production and method platforms.
Platform Coordinator: PD Dr. G. Brunklaus
Forschungszentrum Jülich GmbH
Institute of Energy and Climate Research, Helmholtz Institute Münster (HI MS): Ionics in Energy Storage (IEK-12)
Corrensstr. 46, 48149 Münster
Cross-Sectional Platform Production
A central goal of the production platform is to enable the development and research of scalable and quality-assured production of high-performance solid-state batteries based on solid electrolytes and cell concepts investigated in the cell platforms. To this end, the consortium is mapping the entire production chain on small pilot scale - starting with the processing of composite cathodes and separators of the various material classes using different scalable approaches, through assembly, cell construction and conditioning as well as electrochemical characterization to the economic and ecological evaluation of complete process chains. The individual process steps are investigated using development cells, which are intended both to represent industry-relevant systems and to enable the exemplary investigation of the above-mentioned issues. In contrast to the cell platforms, the focus here is not on the development, optimization, and realization of solid-state battery cells with regard to their electrochemical performance, but on the industry-oriented investigation and evaluation of scalable production processes with quality assurance and the derivation of concrete recommendations for the large-scale production of solid-state batteries.
Method Platform Characterization
This consortium is responsible for the extensive characterization and (further) development of ex situ and in situ characterization methods. It has been shown that particularly the analysis of interfaces will be relevant for further research on solid-state batteries. The consortium is focusing primarily on understanding the stability and degradation processes at the interfaces between cathode particles, solid electrolytes, and other materials in the cathode composite. Suitable protective measures are derived from this. This platform therefore also develops and provides cathode active materials with reproducible and fully characterized protective layers as reference materials for the cluster. The evaluation and development of standardized measurement methods for solid-state battery full cells of different cell concepts is also one of the tasks of this platform.
Platform Coordinator: Prof. H. Ehrenberg
Karlsruhe Institute of Technology (KIT)
Institute for Applied Materials – Energy Storage Systems (IAM-ESS)
Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen
Method Platform Theory and Data
A continuous simulation chain from the atomistic material scale to the macroscopic cell scale is required to be able to develop new cell designs for solid-state batteries with simulation support. Existing battery models are too generic to capture, for example, complex interfacial phenomena in hybrid cell designs or material-specific contributions to interfacial resistances. For the development of material-specific battery models, it is crucial to formulate the macroscopic models in a material-specific way and to systematically parameterize them using data from atomistic simulations, targeted characterization experiments or data-driven inverse modeling. The aim of this platform is therefore to apply the tools for simulation-based cell design to complex cell concepts based on the results in FestBatt and in collaboration with all other platforms. To this end, the focus is on the further development and combination of models, material-specific computer simulations and the application of data analysis techniques. In addition, the Kadi4Mat research data repository for archiving cluster data is being further developed in this consortium.
Accompanying Project Coordination
The accompanying project supports the cluster-internal cooperation of the platforms as well as the cluster-external networking with the management circle, the Federal Ministry of Education and Research (BMBF), the project management organization, the industry, and the general public.
The focus of this subproject is the production of all solid-state batteries using Powder Aerosol Deposition (PAD). PAD is a room temperature spray coating process that can produce dense ceramic layers directly from the raw ceramic powder without a subsequent high temperature step (such as a sintering step). In this subproject, the oxide ceramics NMC (cathode active material) and LLZO (solid electrolyte) are deposited on a metallic collector in the following sequence: first cathode active material (NMC) on the metallic collector, then a graded cathode (mixture of cathode active material and solid electrolyte), and finally pure solid electrolyte. Metallic lithium is pressed on to complete the cell.
The aim of the group, in addition to the electrochemical characterization of the PAD cells, is primarily the model-based design optimization of graded and non-graded composite electrodes. To achieve this, the discrete electrochemical electrode model developed at the department is modified to depict graded electrode by the implementation of parameters that vary across the thickness of the electrode. In addition, the model is parametrized and validated based on various measurements in the frequency and time domain using experimental cells under variable operating conditions (pressure, temperature). This enables a mathematical optimization of the gradient with respect to different criteria such as discharge capacity or energy density. This supports the electrode development process of the project partners and reduces the number of experiments to be conducted. In terms of the electrochemical characterization of the cells and components, a particular focus is on the electrochemical impedance spectroscopy (EIS) and the distribution of relaxation times (DRT) analysis.
The sub-project focuses on re-engineering and validation of advanced, simple, fast, cost-effective, scalable and environmentally friendly powder technological and powder engineering processes for solid electrolyte synthesis and the generation of interface-adapted cathode composite combinations with particular suitability and process capability for the realization of the PAD-supported cell concept. The results of the adapted process parameters and selected interfacial compositions based on LixMyOz-LLZO (M= Ce, Mg, Nb, Ta, and Al) will be used to derive urgently needed data to enable powder aerosol deposition of thick (ca. 130 μm) as well as large-area electrodes. In combination with highly conductive solid electrolytes and electrically conductive additives a targeted interface design of the mixed cathode powders aims to achieve low charge and discharge overvoltage, high Coulomb efficiency, and high cycle stability.
On the materials level, the subproject project FB2-Oxid focuses on the further development of garnet type solid-state electrolytes (LLZO) and cathode active materials with layer structure (NCM) specifically for the application in fully ceramic and hybrid (polymer-ceramic) solid-state batteries. In this context, LLZO and NCM are also synthesized via wet chemical continuous methods and tailored by adjusting their chemical composition and surface coatings. The process chain of critical materials is examined as a whole, including energy input during synthesis and processing. For further processing of the oxide-based materials into cell components (separators and composite cathodes), novel, scalable, and energy efficient manufacturing methods are developed. The manufactured cell components are then combined with a lithium metal anode to full cells with high energy density and characterized electrochemically in detail. More in-depth analyses are performed in cooperation with the cross-sectional platform FB2-Char. The generated data will subsequently be used as a basis for model development and validation in the cross-sectional platform FB2-TheoDat. The materials and cell components produced in the project FB2-Oxid will also be provided to the other subprojects for the realization of their plans.
In the subproject, ceramic full cells with Li1.3Al0.3Ti1.7(PO4)3 (LATP) as solid electrolyte and cost-effective electrode materials (LiFePO4 and Li4Ti5O12) are developed. Multi-layer structures are applied by different casting and printing techniques (tape casting, screen printing) and fabricated by innovative sintering technology (cold sintering) at low temperatures (T < 300 °C) and less energy consumption. High ionic and electronic conductivity of the electrodes and low thickness of the solid electrolyte separator are focused. Hybrid cell concepts of different material groups (ceramic separator, thiophosphate-based cathode) are realized and the effects at the oxide/thiophosphate interface are studied. Wet chemical coating of cathode active materials using scalable continuous spray drying will be developed for this cell type. In addition, polymer layers will be introduced between Li7La3Zr2O12 (LLZO) separator and Li6PS5Cl (LPSC) electrolyte in the cathode to enable high ionic conductivity at low pressure. The aim is to combine advantageous material properties of the oxides (electrochemical stability) and thiophosphates (ionic conductivity) in a hybrid cell concept.
Oxidic solid-state battery cells have traditionally been explored using a separator-supported cell architecture. However, the thickness of the separator imposes limitations on the cell's energy density and its practical utility. In these specific projects, the objective is to manufacture high-energy-density oxidic solid-state battery cells by employing a cathode-supported cell architecture, incorporating a thin-film lithium lanthanum zirconate (LLZO) electrolyte. We are investigating innovative production methods involving the deposition of a thin-film electrolyte onto a free-standing sintered cathode substrate. Pulsed laser deposition (PLD) is utilized to reduce the processing temperature of the electrolyte and achieve a thinner layer, typically in the range of several microns. Our primary focus is to analyze the impact of cathode substrate properties (microstructure and composition) and electrolyte thickness on factors such as ionic conductivity, microstructure, interfacial resistance, and electrochemical performance. This analysis is conducted for both cathode half-cell configurations and full cells featuring a lithium metal anode.
P1 - Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research, Helmholtz Institute Münster (HI MS): Ionics in Energy Storage (IEK-12)
Prof. M. Winter
PD Dr. G. Brunklaus
Prof. H. Wiemhöfer
The work at HIU within the framework of FB2-Poly builds on the already very good results of FestBatt I. The goals are the successful further development, optimization and scaling of the most promising polymer electrolyte systems - both via so-called "single layer" solutions and through the synergistic combination of different polymer systems in "multilayer" solutions. Complementary to this, macromolecular functional layers will be developed to stabilize the interface with the lithium-metal anode and the cathode and ensure efficient charge transfer. The work is accompanied by a comprehensive and systematic physicochemical and electrochemical characterization and inter-laboratory tests to ensure that the results can be obtained independently of people and machines.
In this project, cell components such as composite electrodes and separators are manufactured with thiophosphate solid electrolytes from the project partners. These will be extensively investigated electrochemically and microstructurally in order to be able to identify the limitations of the cell components. The results can be used to optimize the materials and processing methods. The optimized cell components will be used and tested in full cells to determine the performance of solid-state batteries and define the operating windows. Thus, optimized solid-state batteries based on thiophosphate solid electrolytes will be developed. Pouch cell solid state batteries will be fabricated and characterized chemically as well as electrochemically.
The Zeier group at the Inorganic and Analytical department at the university of Münster investigates electrochemical processes with emphasis on solid state ionics and the characterization of solid electrolytes and solid state batteries. To reduce the resistance of solid electrolytes towards the cathode active material, the ionic conductivity of sulfide- and halide-based solid electrolytes is optimized by means of ionic substitution. These solid electrolytes achieve sufficient ionic conductivities to ensure fast ionic transport within the composite cathode. Furthermore, solid electrolytes are modified by means of substitution or through the use of additives to tailor the cathode electrolyte interface. The goal is to intentionally design the decomposition layer between solid electrolyte and cathode active material.
The primary objective of the project is the development of conductivity-optimized sulfidic lithium solid electrolytes in interaction with anode and cathode materials. The development of scalable synthesis and processing concepts for separators as well as for catholytes in solid-state batteries is a focus of this project. Furthermore, the aspects of areal loading to increase energy density, air stability and long-term stability to improve cycling stability, as well as microstructure control, which are crucial for the success of solid-state batteries, will be investigated.
The aim of the subproject is the development and evaluation of scalable process routes along the value chain from material synthesis to cell construction of sulfide-based solid-state batteries. Building on the findings of previous projects, the production of separators and composite cathodes using solvent-based, as well as solvent-free routes will be further deepened and optimized. Addressed optimizations are, for example, the reduction of the separator thickness or the optimization of the microstructure of the composite cathodes. In addition, new, alternative process routes will be considered, such as the processing of composite anodes for Li-free cell concepts. The processes are developed iteratively considering process-structure-property relationships. The produced separators and composite electrodes are characterized and evaluated in pouch cells during the process.
Sulfide-based solid electrolytes show the highest ionic conductivities and at the same time the lowest material availability and high synthesis times. Scalable process technologies for the production of these electrolytes still have to be established. In addition to production, processing in a composite cathode also poses challenges, since the solid/solid interfaces (e.g. active material/solid electrolyte) are often unstable or inhomogeneous. For the production of electrodes various coating methods, such as dry coating, wet coating or printing are possible and need to be evaluated. Therefore, the goals of this subproject at the Fraunhofer IST are the further development and optimization of a scalable mechanochemical synthesis, which was developed within FestBatt I, and the investigation of a screen-printing process of sulfide-based cathodes for solid-state batteries.
In this project within the joint project FB-Thio, the focus is on the processing of thiophosphate-based separators using scalable methods. The goal is to be able to produce thin separators with high ionic conductivities. In particular, the use of a slot dye coating is being pursued as a novel approach. At the Fraunhofer IFAM, chemically stable and rheologically adapted slurries are produced and suitable process parameters are evaluated. In addition, this method can also be used for cell construction by coating separators directly onto dried composite electrodes.
In the material platform "Thiophosphates" Fraunhofer IWS researchers develop processes and cells for a new anode concept based on porous carbons. This approach aims to solve a fundamental problem of the lithium metal anode (morphological instability above critical current density). The carbon framework turns the 2-dimensional into a 3-dimensional interface at which metallic lithium can be reversibly deposited. If successful, the thickness change of the cells and the need to apply external pressure can also be significantly reduced.
In the material platform "Thiophosphates" TU Dresden researchers develop materials for a new anode concept based on porous carbons. Aim is to provide a carbon framework with a 3-dimensional interface at which metallic lithium can be reversibly deposited. The materials are being investigated by advanced structural and electrochemical characterization methods. The processing and integration in pouch cells is done in cooperation with Fraunhofer IWS.
H1 - Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research, Helmholtz Institute Münster (HI MS): Ionics in Energy Storage (IEK-12)
PD Dr. G. Brunklaus
Prof. M. Winter
Dr. N. Vargas-Barbosa
The work at HIU within FB2-Hybrid builds on the already very good results for the development of polymer-based electrolyte systems in FestBatt I. The goals are the successful development, optimization and validation of intelligent hybrid electrolyte systems based on a ceramic and a polymer phase. For this purpose, various cell concepts and electrolyte architectures are being developed, with a focus on the development of suitable polymer phases for such systems, including their incorporation into the ceramic phase and vice versa. The work is accompanied by a comprehensive and systematic physicochemical and electrochemical characterization and inter-laboratory tests to ensure that the results can be obtained independently of people and machines.
This subproject addresses the material design of oxidic solid electrolyte particles for polymer/oxide hybrid electrolytes by doping and functionalization. The oxidic particles are utilzed to prepare polymer/oxide hybrid electrolytes (ceramic-in-polymer, CIP and polymer-in-ceramic, PIC) and are to be processed with the polymers to form both homogeneously mixed and gradient structures. The hybrid electrolytes should enable good coupling at the anode and cathode, and the gradient layers should also prevent dendrite growth. The goal is to find hybrid materials that have good mechanical stability and high ionic conductivity. The development of the necessary material combinations is carried out in close cooperation with the cross-sectional platform "Theory & Data" and the platform "Polymers".
In this project, the interface of lithium metal with hybrid solid electrolytes is primarily considered. In particular, the development of the so-called "anode-free" deposition of lithium on the solid electrolyte separator is aimed at. In addition, cells in pouch format are to be manufactured and electrochemically tested. For this purpose, the development of the film casting process for thiophosphate solid-state batteries and the identification of the right polymer type, properties, amount, and composition are relevant. To achieve these goals, the use of polymer electrolytes in composites appears to be useful due to their versatile mechanical properties. The goal is to develop innovative solutions that enable low interfacial resistances and high-performance solid-state battery.
The central goal for the hybrid platform in the Zeier working group, is the development of thiophosphate-polymer hybrid separator membranes for solid-state batteries through solution processing of the solid electrolyte. By combining both classes of the materials, the challenges such as dendrite growth, crack formation, high thickness of the solid electrolyte layer or processability could be addressed. However, it is associated with enormous challenges. For example, developing suitable fabrication methods, like infiltration of commercial porous polymer membranes, finding chemical and electrochemical compatibility of polymer, thiophosphate and solvents or avoiding additionally occurring phase boundaries during the fabrication process are crucial in this regard. Spectroscopic, gravimetric, microscopic and electrochemical techniques are used to analyze these membranes. Whether hybrid solid electrolyte systems can keep up with conventional ceramics as well as polymers is one of the fundamental questions that AK Zeier at the Inorganic and Analytical department at the University of Münster and the FestBatt Hybrid platform are addressing.
The objective of this sub-project is to develop a dry coating process to produce hybrid separator layers and hybrid cathodes. For this purpose, homogeneous powder mixtures are produced from polymer, ceramic and cathode active material and these are processed into dense cell components in a hot pressing process. In addition to the development of the essential process steps (mixing, powder dosing, compacting), the possibility of building multilayer coatings will also be investigated. To validate the results, cells will be manufactured from the components produced at ISIT and electrochemically characterized.
The aim of the work at the Institute of Particle Technology is the reproducible production of cathodes based on different solid electrolytes under ecological and economic evaluation of the process chain. Depending on the material class, process windows are identified for individual process steps and process-structure-property relationships are derived through targeted variation of the process parameters and subsequent characterization of the components. The focus of all work is on an industry-oriented investigation and evaluation of scalable production processes with quality assurance as well as the derivation of concrete recommendations for the large-scale production of SSB.
The central objective of the production platform is the research and development of a scalable, quality-assured production of high-performance solid-state batteries based on the solid electrolytes investigated in the cell platforms. The focus is on the industry-oriented investigation and evaluation of suitable production processes and the derivation of recommendations for the industrial production of solid-state batteries. First, a technical evaluation of various process routes for the production of solid-state batteries is carried out. Based on the results, quality gates for the suitable process routes are derived. Innovative inline sensor technology is then implemented at a suitable point in the manufacturing process. The focus of the investigations is on cell assembly and conditioning.
The objective of the project is the development of a scalable, quality-assured production of high- performance solid-state batteries (SSB) based on solid electrolytes (SE) investigated in the cell platforms. Within the subproject, the processing of composite cathodes of the different material classes by means of scalable approaches, as well as the assembly and cell construction are investigated. Through structural and electrochemical characterisation using development cells, an evaluation of the cathode production process and cell production will be carried out. Based on the characterisation of handling-relevant material properties (e.g. mechanical stiffness, abrasion resistance), the Institute of Machine Tools and Production Engineering is developing suitable handling processes and quality controls for cell assembly. With a pilot-scale production, multilayer cells will be assembled and the influence of process-immanent loads (e.g. mechanical loads, particle contamination) on the electrochemical performance of the cells will be analysed. In addition, the effects of the placement accuracy and the process atmosphere in the stack formation are investigated in relation to the cell performance. The focus here is on an industry-oriented investigation and evaluation of scalable production processes with quality assurance as well as the derivation of concrete recommendations for action for the large-scale production of SSB.
The overall objective of the FB2-Prod research project is to investigate and advance the scalable and quality-assured production of high-performance solid-state batteries based on the solid electrolytes investigated in the cell platforms. Within the project consortium, the entire process chain is covered on a pilot scale, so that the main task is to investigate the production processes by mapping them as closely as possible to industry in the form of development cells. The wbk contributes its competence in production technology and especially in the handling of flexible parts to the research of the assembly behavior of single sheets. The research object of the wbk Institute of Production Science subproject is focused on the investigation of the retooling capability of a format and material flexible assembly line when changing from conventional LIB to SSB. In this context, a process flow model will be developed and its suitability for stacking will be evaluated by means of targeted tests with a gripper prototype.
Improved electrochemical energy storages with long lifetime is a fundamentally important contribution to the sustainable economy. The solid-state battery has a number of advantages if successful: In the discharged state, cells with reservoir-free anodes would be easier to produce at lower cost and with lower energy input. The use of a solid electrolyte avoids the use of fluorine-containing conducting salts and binders. However, a "green battery" cannot be realized through material development alone; its production must also be developed and designed sustainably to the same extent. In the life cycle of a battery, the production phase has the greatest impact regarding costs and environment. The aims of the FestBatt subproject at the Fraunhofer IST are therefore to accompany the process and production developments and to classify them from an ecological and economic perspective. Hotspots will be identified, and support will be provided in the decision-making process towards sustainable, eco-efficient production.
Different coating processes are being evaluated for the establishment of a manufacturing process for polymer separators. The suitability of different processes (doctor blade, slot die, printing) for selected polymer electrolytes and the influence of the process parameters on the coating quality are investigated and evaluated. Processes for the production of free-standing polymer separators as well as for direct deposition on composite cathodes are considered. The aim is to develop a process for the reproducible production of separator layers.
In the platform "Production" Fraunhofer IWS is working on the solvent-free production of composite cathodes (thiophosphate/NMC) and sulfidic separators. The process will be demonstrated in a continuous powder-to-roll process and is thus another example of the application possibilities of the DRYtraec® technology.
The central goal of the project is the research and development of a scalable, quality-assured production of high-performance solid-state batteries based on the solid electrolytes studied in the other platforms. An important aspect is the development of conditioning strategies for solid-state batteries, whereby the influence of various conditioning parameters (pressure, temperature, current density …) on the cell performance is evaluated. The technical challenges of the implementation of conditioning protocols is assessed. Based on the relevant conditioning parameters, End-of-line testing protocols are developed. It is investigated to what extent end-of-line tests can be combined with the optimized conditioning parameters in order to show ways for a more economical production.
In this project, coated cathode materials for FestBatt2 are produced and characterized by X-ray diffraction. The aim is to provide cathode material with reproducible and characterized protective layers for all project partners. The AP1 (KIT, IAM-ESS) delivers and optimizes coated reference cathode material depending on the cell type and progress of knowledge. The coating process is scaled up to kg scale. The AP2 (KIT, IAM-ESS) investigates phase formation and structure of the materials including possible defects. The materials are also examined with respect to temperature and cycle stability. The obtained structural data are provided to the platform ‘Data’ for recording within the database Kadi4Mat and for modeling promising materials. On the other hand, the results are directly incorporated into the optimization and adaptation of the process and synthesis routes of the material platforms.
In this subproject, Electrochemical Strain Microscopy (ESM), an Atomic Force Microscopy based technique, is employed to draw conclusions regarding the mobility of lithium ions within battery materials. To achieve this, an alternating voltage field is applied between the tip of the cantilever and the sample. The consequence of this field is a periodic oscillation of the ions synchronized with the field. This oscillation is then transmitted to the tip in contact with the surface and can be measured. The amplitude and phase provide information about the local heterogeneity of lithium ion conductivity as well as variations in material composition.
The aim of this project is the quantitative structural characterization of ASSB materials on length scales ranging from micrometers to the atomic scale. This knowledge will also contribute towards the establishment of a data base on ASSB materials. On the one hand, global structure, crystallite orientation and composition of composites as well as coatings are quantified using electron microscopic techniques. On the other hand, the atomic arrangement and the local composition across various interfaces is tackled. The material basis investigated comes from the characterization platform itself as well as from the other platforms. In-situ experiments are undertaken to increase the understanding of processes during cycling and calcination.
The project has the central goals of comprehensively characterizing the internal interfaces and the derived understanding of the interfacial reactions in solid-state batteries. The construction of high-performance solid-state batteries requires the use of cathode composites on the one hand, and efficient anode concepts on the other. The project therefore deals specifically with the complex interfaces in cathode composites as well as the interfaces between solid electrolyte separator and lithium in "anode-free" cells.
The aim of the project is the harmonization of testing procedures for all solid state batteries as well as the detailed electrochemical characterization of the four different FestBatt cell types. The focus lies on the adaption and further development of highly resolving characterization methods as well as the standardization of electrical testing procedures. The harmonization of the testing procedures and the transferability as well as the reproducibility is assured in Round-Robin tests. For the electrochemical characterization, established techniques in the field of conventional lithium ion batteries are transferred to all solid state batteries and specific questions are examined. Here the focus especially is on the development of testing procedures and the realization of measurements with respect to the dendrite stability.
The sub-project is developing a cross-cluster research data infrastructure for solid-state battery systems to enable transparent, efficient and sustainable knowledge-based material development through FestBatt. For this purpose, the virtual research environment Kadi4Mat, which has already been introduced in the context of the first funding phase of FestBatt, will be further developed, as well as supplementary tools. Another focus is the development and application of data science methods in battery research, such as statistical data analysis and machine learning algorithms. Both developments are to be closely linked to enable the analysis of large and complex data sets.
Targeted, application-oriented cluster work and objectives, a highly networked internal structure and the transdisciplinary nature and size of the cluster require an efficient, accompanying coordination and support structure. To this end, the FestBatt accompanying project coordinates the cluster work and ensures successful communication and interaction between the platforms both within the cluster and in exchange with the management circle, industry, the BMBF, the project management organization, the other clusters of competence and the public. Therefore, the organization of cluster-internal and external events as well as the representation of relevant cluster results at conferences and public events is part of this project. In addition, all information from the cluster and on the international status of developments in solid-state battery technology is communicated to the management circle acting in an advisory capacity, the BMBF and the project management organization. This is intended to enable a holistic evaluation of the progress of the cluster and the projects. In addition, the development of a project-related database in the Kadi4Mat repository is accompanied in close cooperation with all platforms and the quality of the data is monitored. A cross-cluster evaluation of developments in the field of solid electrolytes and solid-state batteries is also ensured, so that the current national and international state of the art in science and technology is integrated into the research work of the cluster.