@phdthesis{Rumpel2024,
  author    = {Rumpel, Matthias},
  title     = {Development of Components for Solid-State Batteries and their Characterization},
  doi       = {10.25972/OPUS-34715},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-347154},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2024},
  abstract  = {This Ph.D. thesis has addressed several main issues in current ASSB research within four studies. Ceramic ASSBs are meant to enable the implementation of Li-metal anodes and high voltage cathode materials, which would increase energy density, power density, life time as well as safety aspects in comparison with commercially available liquid electrolyte LiBs. In this thesis, several scientific questions arising on the cathode side of ASSBs have been focused on. With respect to the target system of a ternary composite bulk cathode consisting of ceramic active material, ceramic SSE and an electrically conductive component, studies about the thermal stabilities of these components and their impact on the electrochemical performance have been conducted. Particulate bulk cathode composites have to fulfil electrochemical, chemical, mechanical and structural requirements in order to compete with commercial LiBs. Particularly, the production process requires high-temperature sintering to obtain firmly bonded contacts in order to maximize the electrochemically active area, charge transfer and ionic conduction. However, interdiffusion, intermixing and decomposition of the initial components during sintering result in low-performing ASSBs so far. These side reactions during high-temperature treatment have been investigated in order to gain a better understanding of these mechanisms and to enable a better controlling of the manufacturing process as well as to simplify the choice of material combinations. The first two parts of this thesis deal with the thermal stability of the ceramic SSE LATP in combination with various active materials and with the validation of a probable improvement of the sintering process due to liquid phase sintering of LATP by adding Li3PO4. In the third and fourth parts, the impact of interdiffusion, intermixing and decomposition on the electrochemical performance of TF-SSBs based on the active material LMO and the ceramic SSE Ga-LLZO has been investigated.},
  subject      = {Elektrochemie},
  language  = {en}
}
@phdthesis{Hofmann2022,
  author    = {Hofmann, Michael},
  title     = {Overcoming Obstacles in the Aqueous Processing of Nickel-rich Layered Oxide Cathode Materials},
  doi       = {10.25972/OPUS-27378},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-273787},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2022},
  abstract  = {The implementation of a water-based cathode manufacturing process is attractive, given the prospect of improved sustainability of future lithium-ion batteries. However, the sensitivity of many cathode materials to water poses a huge challenge. Within the scope of this work, a correlation between the water sensitivity of cathode materials from the class of layered oxides and their elemental composition was identified. In particular for the cathode material LiNi0.8Co0.15Al0.05O2 (NCA), the processes taking place in aqueous medium were clarified in detail. Based on this knowledge, the surface of NCA particles could be specifically modified, which led to a reduced water sensitivity. As a result, the electrochemical performance of cells with water-based NCA cathodes was significantly improved and a remarkable long-term cycling performance was achieved. The present work contributes to a deeper understanding of the water sensitivity of cathode materials and at the same time presents a promising approach to overcome this obstacle. Consequently, this work advances the successful widespread realization of water-based cathode manufacturing.},
  subject      = {Elektrochemie},
  language  = {en}
}