E-TIP : Effect of Texture on the electrode-electrolyte Interface Properties in all-solid-state Li-batteries

• Applicant: Dr. Melanie Finsterbusch-Rosen, since 9/2022
• Subject Area: Glass, Ceramics and Derived Composites ; Solid State and Surface Chemistry, Material Synthesis
• Term: since 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 429409150

The key limiting factor for the current advancement of solid-state batteries is ascribed to a high internal resistance for lithium-ion transfer over the solid-solid electrode-electrolyte interfaces, negatively affecting electrochemical performance of ASSBs and reducing cycle life. The effect of the lattice mismatch of the cathode and the electrolyte on the interface resistance and electrochemical performance of all solid state LLZO/LCO-based ASSBs has not been investigated experimentally to the best of our knowledge. The objectives of the proposed project include studies of synergetic effect of co-doping of LLZO with Ga and Ta, potentially leading to increased conductivity and stability in contact with LCO at elevated temperatures, inhibiting interphase formation and thus reducing the LCO/LLZO interface resistance; and of the influence of crystallographic co-orientation of electrolyte and electrode on the electrochemical performance of LLZO/LCO-based ASSBs.First, in order to fabricate textured polycrystalline LLZO electrolyte, structure-properties relationship of Ta and Ga co-doped LLZO solid solutions will be studied as a function of composition. A self-texturing effect in LLZO ceramics has been observed only for Ga-doped material and its mechanism is yet not fully understood. To clarify this effect on a mechanistic level and possibly exploit it for the fabrication of textured LLZO ceramics, the crystal structure, microstructure and electrochemical properties of LLZO co-doped with Ga and Ta LLZO will be subject of the proposed investigations since the structural impact of both dopants is dissimilar. Then dense textured LLZO ceramics of a selected composition will be fabricated by hot pressing or SPS techniques. Additionally, LLZO single crystal rods will be grown by floating zone or Czochralski crystal growth methods. The specimens will be cut and thoroughly polished to obtain LLZO-surfaces with different crystallographic orientations to be used as substrates for cathode thin film deposition.Finally, LCO thin films with varied crystallographic orientation will be deposited by substrate- or nanosheet-templated approach on textured polycrystalline or single crystal LLZO electrolyte substrates and serve as model systems for the investigation of the effect of crystallographic co-orientation of electrolyte and electrode on the electrochemical performance of all solid state LLZO/LCO-based ASSBs. To study the effect of the compressive strain caused by the lattice mismatch of LCO and LLZO in dependence of their crystallographic co-orientation on the delithiation induced structure evolution of LCO, atomic-scale observation will be recorded using advanced in situ TEM technique.These investigations will provide fundamental information about the Li+-transport properties as function of the crystallographic co-orientation of LLZO and LCO as well as contribute to the development both of bulk and thin film LCO/LLZO-based ASSBs.

• DFG Programme: Research Grants
• International Connection: Netherlands
• Cooperation Partner: Professor Dr. Mark Huijben
• Ehemalige Antragstellerin: Dr. Yulia Arinicheva Skåtun, until 8/2022