Periodic Reporting for period 3 - ASTRABAT (All Solid-sTate Reliable BATtery for 2025)
Periodo di rendicontazione: 2022-07-01 al 2023-12-31
The work performed in ASTRABAT wishes to find optimal solid-state cell materials, components and architecture that could well suited to the demands of the electric vehicle market and identification of process for manufacturing in mass production.
Five ambitious objectives were assessed during the project.
1. Development of materials for a solid hybrid electrolyte and electrodes enabling high energy, high voltage and reliable all-solid state Li-ion cells. The ASTRABAT cell is based on a hybrid electrolyte (two polymers) and an inorganic conductive ceramic filler : Li7La3Zr2O12 (LLZO). The two polymers were tailored to the specific materials electrodes, ORMOCER® as anolyte and fluoropolymer as catholyte. Series of Li-salt were synthesised to optimise the ionic conductivity in polymers electrolyte. The ionic conductivity of the solid electrolytes reached 0.4 mS/cm at 50°C. Electrode materials considered at the cathode is a NMC-based material with low cobalt content and at the anode, new nanostructured composite Silicium based material allowing achieving high energy density. To achieve this objective of high energy cell density, adaptation of interface material was done.
2. Development of a cell considering processing techniques compatible in a large scale manufacturing For this purpose, we developped the formulation of electrodes and electrolyte considering the case of electrode-electrolyte architecture based on the use of classical process of electrode coating (tape casting) with polymer electrolyte and conductive ionic ceramic electrolyte (LLZO) infiltrated inside electrode material. 1 Ah cell prototypes were manufactured with a pre-pilot line and reached 176 Wh/kg and 501 Wh/l, lower than the expected KPI due to Si irreversibility and low electrode loadings. Lower C-rates were required to maintain a high discharge capacity (C/10) while lab-scale cells could be cycled at higher C-rates (C/2). Up to 70 cycles were realized and a capacity loss of 25% was recorded for the 1 Ah prototypes.
3. Considering next generation of all solid state battery, we developed eco-designed P-Type (power) and E-Type (energy) of all-solid state battery in pre-prototype. Two type of electrode structure was considered. The first electrode structure is based on the use of nano-wire or nano-rods of LLZO to favour the ionic conduction inside the electrode. Secondly, nano-structured electrodes with different designs (pillars, honeycombs) were fabricated by ink-jet printing and screen-printing. This work was supported by modelling. Despite the strong benefits of ink-jet printing, we demonstrated the difficulty to print uniform layers with good electrochemical properties.
4. All these cells development must support the definition of an efficient cell architecture to comply with improved safety demands. We demonstrated no thermal runaway of the cells at 180°C and no flammable electrolyte, no leakage, no gas formation during cycling.
5. The eco-design of the new cells was developed through a life cycle assessment as well as recycling tests. 65% of the cell compounds is recyclable, reaching the KPI of the project. The cost of the cell prototypes was evaluated and reached 180 €/kWh, still higher than the targeted KPI.
In conclusion, the ASTRABAT solid-state cell offers promising properties but it is still in a rather early stage of development before industrialization.
Five ambitious objectives were assessed during the project.
1. Development of materials for a solid hybrid electrolyte and electrodes enabling high energy, high voltage and reliable all-solid state Li-ion cells. The ASTRABAT cell is based on a hybrid electrolyte (two polymers) and an inorganic conductive ceramic filler : Li7La3Zr2O12 (LLZO). The two polymers were tailored to the specific materials electrodes, ORMOCER® as anolyte and fluoropolymer as catholyte. Series of Li-salt were synthesised to optimise the ionic conductivity in polymers electrolyte. The ionic conductivity of the solid electrolytes reached 0.4 mS/cm at 50°C. Electrode materials considered at the cathode is a NMC-based material with low cobalt content and at the anode, new nanostructured composite Silicium based material allowing achieving high energy density. To achieve this objective of high energy cell density, adaptation of interface material was done.
2. Development of a cell considering processing techniques compatible in a large scale manufacturing For this purpose, we developped the formulation of electrodes and electrolyte considering the case of electrode-electrolyte architecture based on the use of classical process of electrode coating (tape casting) with polymer electrolyte and conductive ionic ceramic electrolyte (LLZO) infiltrated inside electrode material. 1 Ah cell prototypes were manufactured with a pre-pilot line and reached 176 Wh/kg and 501 Wh/l, lower than the expected KPI due to Si irreversibility and low electrode loadings. Lower C-rates were required to maintain a high discharge capacity (C/10) while lab-scale cells could be cycled at higher C-rates (C/2). Up to 70 cycles were realized and a capacity loss of 25% was recorded for the 1 Ah prototypes.
3. Considering next generation of all solid state battery, we developed eco-designed P-Type (power) and E-Type (energy) of all-solid state battery in pre-prototype. Two type of electrode structure was considered. The first electrode structure is based on the use of nano-wire or nano-rods of LLZO to favour the ionic conduction inside the electrode. Secondly, nano-structured electrodes with different designs (pillars, honeycombs) were fabricated by ink-jet printing and screen-printing. This work was supported by modelling. Despite the strong benefits of ink-jet printing, we demonstrated the difficulty to print uniform layers with good electrochemical properties.
4. All these cells development must support the definition of an efficient cell architecture to comply with improved safety demands. We demonstrated no thermal runaway of the cells at 180°C and no flammable electrolyte, no leakage, no gas formation during cycling.
5. The eco-design of the new cells was developed through a life cycle assessment as well as recycling tests. 65% of the cell compounds is recyclable, reaching the KPI of the project. The cost of the cell prototypes was evaluated and reached 180 €/kWh, still higher than the targeted KPI.
In conclusion, the ASTRABAT solid-state cell offers promising properties but it is still in a rather early stage of development before industrialization.
The technical activities of the project includes materials development, coin and pouch cells optimization, scaling-up, LCA, recycling and safety tests.
For the catholyte development, two main strategies were employed to improve the material properties: a blending approach and the use of additives beyond the plasticizer (Ionic liquid) and the LLZO ceramic particles. A focus on the LLZO synthesis and process of functionalisation of it to preserve it from CO2 attacks and enhance the Li+ transport was also carried out.
For the development of electrode materials involving tape casting, two different electrode preparation routes were tested and evaluated – the classical slurry route followed by infiltration of the electrolyte components and an electrode slurry route where the electrolyte is included in the slurry itself. Understanding the properties of the various electrolyte formulations permitted better comprehend effects that arise when the anode electrolyte and cathode electrolyte interface is formed in the full cells. Based on the process route, it was decided that the LLZO (preferably surface-modified for better transport with the polymer phase) was added only in the electrolyte layer to improve the conductivity.
The last period of the project was dedicated to upscaling. The electrolytes materials were synthetized in kg batches. For the manufacturing of GEN#2D cells, CEA which has a large pilot equipment (TRL6-7) in dry room manufactured rolls of porous Si-electrode and NMC electrodes. The last step of electrolyte coating was performed on them by a tape casting step at Yunasko as well as the cell assembly up to 1 Ah.
The Key Exploitable Results are mainly the materials development (electrodes and electrolytes). These results can be exploited as technology licensing and transfer to pilot and production lines to be commercialised in the next coming years. The development to graft protective layers on LLZO is protected by a patent, as well as the process to fabricate the ASTRABAT solid-state cell by elecctolyte infiltration into the electrode. Their exploitation strategy is the process and product development but further research and scaling-up is required before a possible industrialisation.
In term of results dissemination, two patents and three peer-reviewed papers in open access were published so far. But 2 more patents and more than five publications are in preparation. More than 15 presentations were done in international conferences. The final event gathered the LCBAT12019 cluster and remains available on Youtube (ASTRABAT channel).
For the catholyte development, two main strategies were employed to improve the material properties: a blending approach and the use of additives beyond the plasticizer (Ionic liquid) and the LLZO ceramic particles. A focus on the LLZO synthesis and process of functionalisation of it to preserve it from CO2 attacks and enhance the Li+ transport was also carried out.
For the development of electrode materials involving tape casting, two different electrode preparation routes were tested and evaluated – the classical slurry route followed by infiltration of the electrolyte components and an electrode slurry route where the electrolyte is included in the slurry itself. Understanding the properties of the various electrolyte formulations permitted better comprehend effects that arise when the anode electrolyte and cathode electrolyte interface is formed in the full cells. Based on the process route, it was decided that the LLZO (preferably surface-modified for better transport with the polymer phase) was added only in the electrolyte layer to improve the conductivity.
The last period of the project was dedicated to upscaling. The electrolytes materials were synthetized in kg batches. For the manufacturing of GEN#2D cells, CEA which has a large pilot equipment (TRL6-7) in dry room manufactured rolls of porous Si-electrode and NMC electrodes. The last step of electrolyte coating was performed on them by a tape casting step at Yunasko as well as the cell assembly up to 1 Ah.
The Key Exploitable Results are mainly the materials development (electrodes and electrolytes). These results can be exploited as technology licensing and transfer to pilot and production lines to be commercialised in the next coming years. The development to graft protective layers on LLZO is protected by a patent, as well as the process to fabricate the ASTRABAT solid-state cell by elecctolyte infiltration into the electrode. Their exploitation strategy is the process and product development but further research and scaling-up is required before a possible industrialisation.
In term of results dissemination, two patents and three peer-reviewed papers in open access were published so far. But 2 more patents and more than five publications are in preparation. More than 15 presentations were done in international conferences. The final event gathered the LCBAT12019 cluster and remains available on Youtube (ASTRABAT channel).
Through the project, new Li salts and plasticizers were synthetized, improving the ionic conductivity and stability of the polymer-based electrolytes. A system with two polymers specifically designed for their respective electrode was developped allowing to improve the solid-state cells performances, heir safety and recyclability. Besides, identification of processes to manufacture all solid state battery was addressed, helping for the knowledge and identification of bottleneck for the production of such type of new cells. This will strengthen cell production in Europe by the technological transfer of the ASTRABAT project to industrial partners (Leclanche, Yunasko) or generation of new start up from the project partner entities. It also helped the materials producers (DAIKIN, Nanomakers, and UMICORE) to develop and characterize their materials into cells with the consortium knowledge and expertise.
To reach the impact 7, two workshops were organized and dedicated to the manufacturing. Furthermore, during the third period, the project ASTRABAT participated to 4 large EU events which gave the opportunities to strengthen the European battery value chain with academics, industrials and EU associations participating.
To reach the impact 7, two workshops were organized and dedicated to the manufacturing. Furthermore, during the third period, the project ASTRABAT participated to 4 large EU events which gave the opportunities to strengthen the European battery value chain with academics, industrials and EU associations participating.