Ni-rich oxides synthesised via spray pyrolysis will undergo further benchmarking to identify the best-performing composition. This selection process will entail crystal structure determination and physicochemical characterisation of the powders utilising relevant techniques. Additionally, selected compositions will undergo a granulation protocol using milling to achieve a bimodal particle distribution, facilitating the high packing of particles during electrode processing. The screening process will extend to electrochemical performance evaluation in half-cell configurations using conventional components. Optimisation of particle size and morphology will aim to minimise reactivity between the oxide and sulfide ion-conducting components. Assessment of the catholyte electrolyte may involve sulfide or hybrid oxide-sulfide electrolytes depending on performance and compatibility with the hybrid separator. In dry processed pellets, the analysis will focus on the interface between the cathode and the mixed electrolyte via EIS and the interface towards the current collector. Additionally, the degradation of the sulfide electrolyte in contact with the active material will be investigated, including analysis of phase stability and the impact of density and morphology on electrode performance. These comprehensive analyses will inform the selection and optimisation of materials and interfaces for enhanced battery performance and durability. A structured approach to cathode composite particle formation for both wet and dry processing of electrodes will be established. The powders will undergo processing with uniaxial pressure to reduce porosity. Furthermore, cathode sheets will be prepared by wet processing and different binder systems and conductive additives will be evaluated for slurry-based production. A multilayer process will be investigated to optimise the contact between the separator and cathode. Additionally, the fabrication of cathode laminates using ethanol or methyl alcohol as a solvent and ethyl cellulose as a binder, along with carbon additives, will be explored. Different slurry formulations will be tested to achieve high-capacity loading for the cathode. The thickness, porosity, and morphology of casted electrodes will be assessed using relevant techniques as a function of slurry formulation and applied pressure. This comprehensive approach optimises the cathode electrode manufacturing process and performance for solid-state batteries. The manufacturing process for LiM supported over a Cu substrate involves an evaporation technique. This process can be outlined as follows: Evaporation Deposition of Li Metal onto Cu Substrate:In this step, LiM is evaporated and deposited onto rolls of Cu substrate using a roll-to-roll (R2R) process. This technique allows for the continuous and uniform deposition of lithium metal onto the copper substrate, ensuring consistent quality across the production line. Laminating BOPP Film over Lithium Metal:Following lithium metal deposition onto the copper substrate, a Biaxially Oriented Polypropylene (BOPP) film is laminated over the lithium metal layer. This lamination process is conducted through an R2R operation, ensuring efficient and seamless coverage of the lithium metal layer.The primary purpose of laminating the BOPP film over the lithium metal is to prevent direct contact between lithium layers, which can lead to safety concerns such as dendrite formation and potential short circuits. The BOPP film acts as a barrier, isolating individual lithium layers and enhancing the stability and safety of the overall LiM-supported substrate.Overall, the combination of evaporation deposition of lithium metal onto Cu substrate and subsequent BOPP film lamination represents a comprehensive manufacturing process aimed at producing LiM-supported substrates with enhanced safety and performance characteristics. XPS is a crucial technique for characterising the phase formation and element distribution on the surface of LiM. It provides valuable insights into the Li surface's chemical composition and structural properties. Additionally, the electrochemical performance of Li electrodes was thoroughly evaluated by preparing Li-Li symmetric coin cells. These cells were subjected to various electrochemical tests, including electrochemical impedance spectroscopy (EIS) and stripping/plating cycles, to assess the electrodes' behaviour under different operating conditions. In further trials, which results will be provided later, surface protection layers will be applied over the lithium metal using magnetron sputtering to enhance the stability of the Li-electrolyte interface and mitigate side reactions and dendrite formation. This technique enables the deposition of thin protective layers of suitable inorganic materials onto the Li surface. These surface protection layers stabilise the interface with the electrolyte, reducing the likelihood of detrimental reactions and dendrite formation. Furthermore, the selected inorganic materials for surface protection will undergo rigorous evaluation to ensure compatibility with the hybrid electrolyte, thereby preserving the Li electrodes' overall electrochemical performance and safety. Through systematic characterisation and assessment, this approach aims to optimise the performance and longevity of lithium metal electrodes in advanced battery systems.
Hary et al. (Fri,) studied this question.