Modeling Li Dendrite Formation in All-solid-state Lithium-ion Batteries

Li metal is considered as an ideal candidate for anode material of high energy all-solid-state Lithium-ion-batteries(ASS LIBs). Theoretically, using solid-state electrolytes(SSEs) with good mechanical strength is able to suppress Li dendrite growth. The dendrite problems still exist in ASS LIBs with Li anode as demonstrated in many studies. We present a 3D meso-scale model of ASS LIBs using the Lattice Boltzmann Method(LBM) that incorporates ion transport in the SSEs based on the Nernst-Planck equation and reaction kinetics at the electrode/electrolyte interface using modified Butler-Volmer equation. The porous geometries of the SSEs were included and their effects on the maximal transport ability of the system were studied. The results show that diffusion-limited current decreases as porosity increases or transport parameter decreases. The model was applied to simulate galvanostatic charge processes of ASS LIBs under various charge conditions. Using this approach, we obtained Li ion concentration in the electrolyte and captured the Li dendrite formation behavior. The dendrite growth and morphology which are attributed to inhomogeneous ion activities are not only dependent on the charge current and transport parameter but also associated with porous nature of the SSEs.