Building a Setup to Investigate the Influence of Pressure on Electrodes in Solid-State Batteries

This master's thesis aims to design and construct an experimental setup to examine the effects of external pressure on solid-state batteries (SSBs). The setup, designed for electrode-level SSB materials, utilizes an 18 mm diameter sample size, larger than commonly used in similar research, to provide more representative data. The setup includes a durable pressure cell accommodating various SSB materials, a precision pressure system capable of maintaining stable pressures up to 300 MPa, and an integrated real-time monitoring system for pressure and electrochemical cycling measurements. Calibration ensured the setup's reliability and accuracy. Experiments were conducted at 50°C to maintain consistent conditions. The research visualizes the "breathing" phenomenon of electrode materials, specifically Li against LFP in PEO-based electrolytes, characterized by volumetric changes during lithiation, where Li ions migrate to LFP causing increased pressure, and during delithiation, where the reverse occurs leading to decreased pressure. This shows the mechanical stresses and structural dynamics within SSBs, critical for improving battery design and safety. This breathing phenomenon helps to understand relationship between Li ions, electrode materials, and electrolytes in solid-state batteries. Notably, the findings from the experiments reveal a significant enhancement in ion conductivity and overall battery performance with increased pressure. In summary, this thesis provides valuable insights into the importance of pressure optimization for the development of efficient and long-lasting solid-state batteries. The results obtained from this study contribute to advancing the understanding of SSB technology, emphasizing the potential for developing safer and more efficient energy storage solutions.