Search

The novel electrode design, which is a diffusion-dependent electrode structure composed only of active materials, can theoretically realize high energy density. The diffusion-dependent electrode structure can transport lithium ions in the entire electrode through lithium-ion diffusion between the active material particles unless the connectivity between the active material particles is cut off. However, since the electrode structure transfers ions through diffusion, if the thickness of the electrode is too thick, there is a possibility that the performance may have deteriorated. For this purpose, by using not only graphite but also silicon particles, it is possible to have a thin electrode structure compared to the same capacity. In this study, graphite-silicon diffusion-dependent electrode according to the silicon particle size is formed into a digital three-dimensional electrode structure and based on this, electrochemical simulation and analysis of an all-solid-state battery having a diffusion-dependent electrode are performed. The importance and cause of the size of silicon particles in the graphite-silicon diffusion-dependent electrode will be investigated. Reference Diffusion-dependent graphite electrode for all-solid-state batteries with extremely high energy density, ACS Energy Letters , 5(9) (2020) 2995-3004 Revisiting TiS2 as a diffusion-dependent cathode with promising energy density for all-solid-state lithium secondary batteries, Energy Storage Materials , 41 (2021) 289-296

An internal short circuit (ISC) is known to be the main cause of fatal accidents in Li-ion batteries (LIBs). If two electrodes come into contact with each other because of any event, the inner temperature of LIBs increases rapidly within the very short time. If the temperature can increase over the threshold temperature, fire or explosion accidents can occur in the LIB, which is called thermal runaway (TR). Because the fire in the LIBs is not easily extinguished and can cause significant damage of life and property, we should understand the fundamental electrochemical and thermal behavior of ISC-TR in order to prevent or delay these severe accidents. For this purpose, there have been tremendous attempts to analyze different ISC cases with a variety of LIB cells experimentally through penetrating nails, pucks, shape memory alloys, etc. However, experimental methods have limitations in measuring internal temperatures and estimating current density and lithium-ion concentration within LIB cells. Also it is still challenging to control the types and locations of ISCs practically. To compensate these experimental limitations, many simulation studies have also been conducted. However, many simulation research have been considering a two-dimensional-based microscale domain, which may have relatively inaccurate simulation results or cannot consider three-dimensional placement, or a three-dimensional-based large domain, which calculates ISC only in mm units or more. In this work, we developed an advanced thermo-electrical model to simulate the responses of LIB cells depending on the sizes, numbers, and locations of lithium dendrites or impurities. This model can calculate the current density, which causes joule heat flux, and simulate heat transfer. Thus, this model can provide us with information on what kinds or how many of lithium dendrites will lead to thermal runaway. Also, it is possible to analyze the thermal behavior of LIBs according to the various physical and temperature conditions of the lithium dendrites.