Protocols and specifications:
- “Safe handling & testing protocol” was established. It includes performance tests, safety tests and accelerated ageing, and detect defects in the cell and define at which point to perform cell post-mortem analysis.
- KPIs and testing protocols were defined according to the calculations and information supplied by the end-user. Energy density/power, cyclability, cost and design targets (technical and cost related) were taken from the cells for battery electric vehicles.
- Automotive specifications were provided to all partners involved in the work packages.
Progress of producing and testing protective layers deposited on anode and cathode of a solid state battery using PLD (Pulsed Layer Deposition):
- PLD was used to coat Lithium metal on to a Cu-foil with a width of up to 10cm. Different thicknesses 5-20um were deposited and evaluated for their electrochemical performance. The thickest layer of 20um showed the best performance.
- Full cells assembled with multilayers manufactured by PLD and NMC cathode prepared by wet processing showed high internal resistance and as a consequence, the cells displayed very poor electrochemical performance using the round-shape pouch cell configuration
- As LPSCl (lithium argyrodite), the sulfide solid electrolyte, is sensitive to moisture, different barriers as LLZO, amorphous carbon and magnesium were evaluated to be deposited by PLD on it's surface for protection. The electrochemical functionality was shown to be limited at the first trials due to the porosity of the sulfide layer and poor interfacial contact. Post- processing to densify layers and improving the interface was challenging due to the soft nature of Lithium. LLZO (1 µm) was deposited by PLD on commercial Cu with Li (10 µm) delivered the best electrochemical result so far of the tested barriers.
Electrochemical results from the tests showed:
- Symmetric cells with PLD-Li metal anodes cycled 160 h at a current density of 0.15 mA/cm2 and capacity of 0.3 mAh/cm2
Symmetric cells with PLD-Li-LLZO samples cycled around 550 h at a current density of 0.15 mA/cm2 and capacity of 0.3 mAh/cm2
Commercial Li-on-Cu: Cycling 1250 h at 0.15 mA·cm-2 (0.3mAh/cm2)
- Cu - ~20 µm Li (commercial) - ~2 µm LLZO ~25 µm LPSCl (GEN 2) shows interesting results.
- The cathode chosen was NMC90505, dry processed, displayed 200 mAh/g at C/20. NMC cathodes, wet processed, showed 165 mAh/g at C/30, that is less than the cathodes processed by dry processing. Finding a binder system that can be scaled up without separating has been challenging.
Modelling:
-Upgraded electrochemical model with new faster solver, sub-models for modelling solid-state half-cell configurations and EIS calculation capabilities.
-Code restructuring of the electrochemical model to be suitable for running larger DoEs (design-of-experiment) on the HPC architecture.
-Performed several case studies by analysing impact of certain parameter variation on the calculated EIS curves.
-Discretised thin layer which represents porous SEI layer on the separator/Li-anode interface was implemented. Impact of this additional layer on the performance of the cell was investigated.
-Developed a workflow to simulate heterogenous particles and numerical simulation of diffusion in them, also with tensorial diffusion coefficients.
-Established the manufacturing workflow for Solid State Battery cathodes with realistic particle geometries extracted from tomography images. Calibration of models based on experimental data.
LCA and Recycling:
-A comprehensive analysis of the current literature on lithium-ion batteries was conducted regarding environmental studies to identify the components /materials/processes with the highest environmental burdens.
-Data collection regarding the PULSELiON production processes to build the life cycle inventory (WP3), was initiated.
-Review on the existing literature on lithium-ion batteries regarding cost analysis was performed to understand the main cost drivers.
-SSBs Recycling Process Flow Design was established). This deliverable defines the conceptual recycling process flow for PULSELiON cells, which was designed based on the research performed.
- Li –Metal is converted to Li-OH salt which can be used in the preparation of CAM materials.
- Leaching efficiency trails are successful at pristine level. However, the solid to liquid ratio needs to be optimized to have better efficiency. Project specific cells are required to test the solution on these cells.
