SOLVE: NEWSLETTER #01

1/14 Grant n° 101147094 NEWSLETTER #01 March 2025 Editors: Quentin Morel ([email protected]) Esperanza Sedano Varo ([email protected]) Andriy Kvasha ([email protected]) Funded by the European Union (Grant n°.101147094) Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union. Neither the European Union nor the granting authority (CINEA) can be held responsible for them. 2/14 Grant n° 101147094 SOLVE consortium met on Tuesday 10 and Wednesday 11 December 2024 for the project's first General Assembly in Torino, Italy. It was a constructive and convivial occasion for all the partners to get to know each other better, share the progress of each task and identify solutions to the technical challenges of the project. 3/14 Grant n° 101147094 As confirmed by our Advisory Board (Umicore, ACC – Automotive Cells Company, and Comau), SOLVE has achieved significant progress in its first six months! The project continues to advance successfully, thanks to the strong collaboration of all partners. On the 10th and 11th of December, the consortium reviewed the project’s advancements across all working groups, with detailed presentations on activities and the challenges encountered. This gathering provided a valuable opportunity to not only identify solutions but also to share experiences across different groups and foster collaboration. The consortium thanks Politecnico di Torino for hosting this two-day event and organizing an insightful visit to the university’s laboratories. We are also grateful to Centro Ricerche Fiat (CRF), which kindly facilitated a visit to their research facilities. We appreciate the efforts of all the work package leaders who presented their latest developments: CIDETEC Energy Storage, CRF, Pulsedeon, Arkema, CEA, and Tenerrdis, as well as to the other contributors: Fraunhofer IKTS, Saft, Pipistrel Vertical Solutions, Oerlikon, Empa, LOMARTOV SL, ACCUREC-Recycling GmbH, and Delfort. Finally, special thanks to the project coordinator, CIDETEC Energy Storage for ensuring the success of this meeting with a lively, animated, and constructive event. Looking ahead, the next General Assembly will take place in six months and will be hosted by Fraunhofer IKTS in Dresden. All will be solid! Tout sera solide! ¡Todo será sólido! Tutto sarà solido! Kaikki on kiinteää! Alles wird solide sein! Vse bo trdno! Thanks to the Advisory Board, which is taking a great interest in this project: 4/14 Grant n° 101147094 The first public deliverables of the project are available on our website, so don't hesitate to consult them. The purpose of this document is to present the graphic identity of the SOLVE project, its graphic universe and the first communication tools: the website and social networks. This document traces the strategy for the dissemination and communication activities of the SOLVE project. It includes a map of the SSB European actors. This document compiles all testing protocols for materials and cell components characterization, as well as for evaluating the cell performance and safety. This document describes technical and non-technical requirements for SSB, lists all design parameters and related KPIs for LiM-SSB and AF-SSB, as defined in Task 1.1 and Task 1.2. 5/14 Grant n° 101147094 Want to find out more about our consortium members? Our LinkedIn page presents them in an original format, with a short interview in 3 questions. ©Battery 2030+ Conference 6/14 Grant n° 101147094 CIDETEC and POLITO will attend Batteries 2030+ conference to present SOLVE CIDETEC will attend ESPE-2 to present project-related results In an increasingly electrified world, where we are almost constantly in close contact with energy storage devices, there is a growing demand for intrinsically safe batteries that eliminate the risk of explosions and ensure user - and environment - safety. Despite recent pessimism, solid state batteries (SSB) are considered as one the most promising candidate or even gamechanger mainly due to expectation of improvement in the terms of energy density, durability and safety comparing to conventional lithium-ion batteries which are considered as the main commercial benchmark. SSB hold great potential across a range of applications, including road transport, aviation, and, more recently, energy storage systems, driven by the need for reliable and high-performance 7/14 Grant n° 101147094 solutions in the face of frequent grid instability events. This potential has driven battery manufacturers and OEMs to establish robust R&D programs and make substantial investments in different SSB technologies. The development and manufacturing of affordable, high performant, safe and sustainable solid state battery cells with a combination of functional properties is not a trivial task. It requires rational balance in the “performance – safety - cost” system via reasonable choice of active and inactive materials, balanced design and harmonization of cell components, adaptation of manufacturing processes, and application advanced digital tools to accelerate the process. Therefore, SSB research and development is extremely complex converging on several critical technologies to address performance, scalability, and, if possible, compatibility with manufacturing infrastructure of existing lithium-ion batteries plants. Currently, main SSB R&D efforts are focused on the following areas: • Solid electrolyte is the key component of SSB which makes the main difference comparing to batteries with liquid electrolytes. Polymer-based electrolytes (e.g., PEO, PVDF-HFP, etc.) are one of the dominating research lines due to their flexibility and ease of processing comparing to solid inorganic electrolytes (oxides, sulfides etc.). SSB electrolyte’s development hinges on balancing competing material properties. High ionic conductivity often comes at the expense of mechanical stability (e.g., oxide electrolytes are brittle), while robust mechanical properties may sacrifice the electrochemical performance (e.g., polymers have low room-temperature conductivity). To overcome low room-temperature conductivity of polymer-based electrolytes, hybrid strategies—such as blending polymers with ceramic fillers (e.g., LLZO) and/or plasticizers (ionic liquids, solvents etc.)—are widely explored. These hybrids enhance ionic conductivity while retaining mechanical robustness, enabling thin electrolytes suitable for high-energy cells. Recently, an interesting hybridization approach of a separator supported solid electrolyte has been proposed and demonstrated at pouch cell level1. Also, not self-standing semi-solid electrolytes with relatively high content of liquid components are gaining momentum. • The first choice of negative electrode for SSB is lithium metal which enables drastic increasing of cell energy density due to possibility of suppressing lithium dendrites growth by advanced solid electrolyte. Highly reversible ultra-thin lithium metal anodes (<20 µm) are central to achieving SSBs with energy densities exceeding 700 Wh/kg2. Innovations focus on mitigating lithium dendrites growth and improvement of reversibility of Li stripping-plating process through protective coatings, alloys, use of 3D porous current collectors, via control of SEI growth and the optimization of “electrolyte/anode” interface. Recent advances also target “zero excess” lithium metal anode designs to reduce cost and safety risks at cell level. • Positive electrode for SSB is often an overlooked cell component, especially in case of high loading configuration, though recently they have been gaining the attention of the SSB community since the development of high loading electrodes (>4 mAh/cm2) with optimal balance of CAM (Cathode Active Material), catholyte and conductive additives is one of the major milestones for SSB technology. Classical choice for positive electrode of SSB with PEO-based electrolytes is LiFePO4 which has relatively low energy density but can be operated at 3 V region. High-capacity Ni-rich oxides as 1 https://advanced.onlinelibrary.wiley.com/doi/abs/10.1002/adma.202100353 2 A 700 W⋅h⋅kg−1 Rechargeable Pouch Type Lithium Battery - IOPscience 8/14 Grant n° 101147094 4 V-class CAMs are favoured for SSB for their balance of energy density (>200 mAh/g). However, majority of known polymer-based electrolytes have limited electrooxidative stability especially at high temperature and, as result, poor compatibility with 4 V-class CAMs. To address the interfacial degradation with solid electrolytes, strategies include cathode coatings (e.g., LiNbO₃), gradient doping, and integrating ad-hoc solid electrolyte (catholyte) directly into the active layer matrix of the cathode. • Pouch cell with stacked electrodes and solid electrolyte layers remains the preferred format for SSBs, as they leverage existing lithium-ion manufacturing lines. Their flexibility also accommodates the mechanical stresses inherent in solid-solid interfaces, though challenges like stack pressure optimization persist. On the other hand, the use of winding technologies (jelly roll) and hard case (cylindrical and prismatic) are considered as a promising approach towards SSB industrialization. • The development of a manufacturing process for SSB (for components and battery cells) that can cost-wise compete with LIB one is crucial to overcome a possible production hell3. In particular, roll-to-roll (R2R) manufacturing—adapted from lithiumion technology—is critical for scaling SSB production to reduce the manufacturing cost to LIB level. Some of key steps include (i) R2R fabrication of all cell components to ensure cost-effective throughput while supporting sustainable practices, (ii) manufacturing handling and precision cutting for ultrathin lithium metal foil electrodes and self-standing solid electrolytes, (iii) high speed and precise stacking, and (iv) inline quality control to minimize defects and increase the production yield. Despite these recent technological improvements, several challenges must be addressed to enable the adoption of SSB. For example, currently most SSB cells must be operated at elevated temperatures (often >60 °C) to achieve sufficient ionic transport and acceptable internal resistance. This requirement complicates the thermal management system of the module, often necessitating heating elements that add weight, complexity, and safety risks. Another challenge is directly related to the solid nature of the system. Unlike liquid electrolytes, which impregnate all pores and conform naturally to the electrode surface, solid-solid interfaces in SSBs are prone to have poor contact due to microscopic surface irregularities. Even minor defects (e.g., voids, cracks, or roughness) can create “dead zones” that impede effective ion transport, increase internal resistance, accelerate degradation, reduce cycle life and even cause sudden cell failure. This level of sensitivity imposes exceptionally high demands on manufacturing precision. In addition, there is often observed chemical incompatibility between components—such as reactions between lithium metal and certain solid electrolytes— which can degrade interfaces in the cell over time, forming resistive layers that impact performance. Any solution to these challenges must align with sustainability goals, avoiding energy-intensive processes or exotic materials that complicate scalability and increases the cost. Success will require a holistic approach, integrating breakthroughs in materials science, interface engineering, and production technologies, to unlock SSBs’ full potential. 3 https://spectrum.ieee.org/solid-state-battery-production-challenges 9/14 Grant n° 101147094 Figure 1. SOLVE’s LiM-SSB cell concept. Cidetec Energy Storage (Inicio | Cidetec Energy Storage) Cidetec is a private research centre founded in 1997 with overall workforce of 280+ employees. Cidetec Energy Storage institute involves up to 140+ researchers and is specialised in creating new battery technologies (incl. SSB) according to specific challenges, and its ultimate transference to the industry. The institute has the capacity to develop complete products and processes and offers material validation, pilot manufacturing, pack engineering and battery testing services. The institute is strongly involved in the European battery community, including the core team of BATTERY 2030+ and regular participant and coordinator in HEU funded battery projects. In this context, the EU-funded SOLVE project aims to develop room-temperature, highperformance, cost-effective, and safe-by-design 20 Ah Gen4b SSB prototypes. SOLVE’s approach is built on three key pillars: 1. Hybrid solid polymer electrolytes: Thin (≤30 μm), defect-free electrolytes with high ionic conductivity (>0.5 mS/cm at 25–40 °C) and wide electrochemical stability (>4.7 V vs Li/Li+). 2. High-loading solid-state cathodes: Ni-rich NMC-based cathodes with high loading (>4.0 mAh/cm²) and specific capacity of >200 mAh/g. 3. Ultra-thin lithium metal anodes: thickness <10 µm, and specific capacity of >3,000 mAh/g. All components will be designed for scalability and sustainability, leveraging roll-to-roll (R2R) manufacturing processes. Special attention is given to addressing interfacial challenges and ensuring compatibility between components, which are critical for achieving long-term stability and performance. By combining European expertise in materials innovation, manufacturing, and sustainability, SOLVE is paving the way for the next generation of solid-state batteries, positioning Europe as a leader in this transformative technology.