Assessing the Thermal Safety and Thermochemistry of Lithium Metal All-Solid-State Batteries Through Differential Scanning Calorimetry and Modeling

dc.contributor.advisorAlbertus, Paulen_US
dc.contributor.authorJohnson, Nathan Brenneren_US
dc.contributor.departmentChemical Engineeringen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.date.accessioned2023-06-23T05:55:46Z
dc.date.available2023-06-23T05:55:46Z
dc.date.issued2023en_US
dc.description.abstractSolid-state batteries are often considered to have superior safety compared to their liquid electrolyte counterparts, but further analysis is needed, especially because the desired higher specific energy of a solid-state lithium metal battery results in a higher potential temperature rise from the electrical energy in the cell. Safety is a multi-faceted issue that should be carefully assessed. We build "all-inclusive microcell" Differential Scanning Calorimetry samples that include all cell stack layers for a Li0.43CoO2 | Li7La3Zr2O12 | Li cell in commercially relevant material ratios (e.g. capacity matched electrodes) and gather heat flow data. From this data, we use thermodynamically calculated enthalpies of reactions for this cell chemistry to predict key points in cell thermal runaway (e.g., onset temperature, maximum temperature) and assess battery safety at the materials stage of cell development. We construct a model of the temperature rise during a thermal ramp test and short circuit in a large-format solid-state Li0.43CoO2 | Li7La3Zr2O12 | Li battery based on microcell heat flow measurements. Our model shows self-heating onset temperatures at ∼200-250°C, due to O2 released from the metal oxide cathode. Cascading exothermic reactions may drive the cell temperature during thermal runaway to ∼1000 °C in our model, comparable to temperature rise from high-energy Li-ion cells, but subject to key assumptions such as O2 reacting with Li. Higher energy density cathode materials such as LiNi0.8Co0.15Al0.05O2 in our model show peak temperatures >1300°C. Transport of O2 or Li through the solid-state separator (e.g., through cracks), and the passivation of Li metal by solid products such as Li2O, are key determinants of the peak temperature. Our work demonstrates the critical importance of the management of molten Li and O2 gas within the cell, and the importance of future modeling and experimental work to quantify the rate of the 2Li+1/2O2→Li2O reaction, and others, within a large format Li metal solid-state battery.en_US
dc.identifierhttps://doi.org/10.13016/dspace/ra1j-neuc
dc.identifier.urihttp://hdl.handle.net/1903/29979
dc.language.isoenen_US
dc.subject.pqcontrolledEnergyen_US
dc.subject.pqcontrolledChemical engineeringen_US
dc.subject.pqcontrolledMaterials Scienceen_US
dc.subject.pquncontrolledBatteriesen_US
dc.subject.pquncontrolledEnergy Storageen_US
dc.subject.pquncontrolledLithiumen_US
dc.subject.pquncontrolledSafetyen_US
dc.subject.pquncontrolledSolid Stateen_US
dc.subject.pquncontrolledThermochemistryen_US
dc.titleAssessing the Thermal Safety and Thermochemistry of Lithium Metal All-Solid-State Batteries Through Differential Scanning Calorimetry and Modelingen_US
dc.typeDissertationen_US

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