(Digital Presentation) Measuring Thermal Behavior of Lithium Metal Solid State Microcells with Differential Scanning Calorimetry

Research efforts in developing solid-state batteries with lithium metal anode have been on the rise owing to the high specific energy density cells using lithium metal. An all solid-state battery is often assumed to be safer compared to a Li-ion battery with an organic liquid electrolyte. If the energy density of a cell is increased through the introduction of Li metal, the potential temperature rise of the cell also increases, leading to a reduction in cell safety. In particular, during self-heating Li metal has the potential to react with the cathode itself and/or oxygen released from the cathode upon heating, as well as the solid electrolyte. The rate and extent of exothermic reactions in a specific battery chemistry and configuration determine whether self-heating could be created in a cell, as well as its onset temperature and rate. To quantify the thermal behavior of the reactions that occur within a Li metal solid state cell upon heating, we use differential scanning calorimetry (DSC). For the DSC measurements, we assemble all cell layers inside hermetically sealed stainless sealed pans, which allows us to carry out the analysis in an inert environment. With this platform, multiple cell chemistries and configurations can be tested, and the calorimetry of the reactions taking place among all cell components can be quantified. In this presentation, we will discuss our DSC measurements on select cell chemistries including with LiCoO2 and LiNi0.8Mn0.1Co0.1O2 cathodes at different states of charge, Li7La3Zr2O12 and Li3PS4 solid electrolytes, and a Li metal anode.