Date of Award
Master of Science in Chemical Engineering (MSChE)
Operational safety and cycle stability are important attributes for all rechargeable batteries. To meet these stringent demands specifically for biomedical applications, an all-solid lithium-ion battery (ASLIB) consisting of a polyethylene oxide\ (PEO)-based polymer electrolyte with a lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) salt, lithium titanate (LTO) anode and lithium iron phosphate (LFP) cathode is proposed. This work implements fabrication methods, composition optimizations and an assembly procedure, all tailored to the unique cell chemistry and ending in the all-solid LTO-PEO/LiTFSI-LFP cells. Subsequently, these ASLIBs are tested close to body temperature at 40 °C. This assures solid-state, but augments bulk electrolyte and interfacial resistance compared to frequent investigations of polymer electrolyte cells at even more elevated temperatures. In spite of these drawbacks, LTO-PEO/LiTFSI-LFP cells are successfully charged/discharged with a C-rate of C/20. In order to understand observed capacity fading, the cycling behavior of these cells is related to several electrochemical phenomena through impedance measurements and investigations of respective half- and symmetric cells. In the end, a unique electrode composition and assembly procedure is proposed to minimize interfacial resistance.
Duwe, Lukas, "ALL-SOLID LITHIUM-ION BATTERIES FOR HIGH SAFETY AND STABILITY" (2019). Open Access Master's Theses. Paper 1503.