Abstract
Ions are at the core of the mechanism involved in electrochemical energy storage. However, it remains difficult to physically measure the local ionic transport inside a working device. Limiting factors in the local transport in miniaturized electrochemical energy storage (MEES), especially in 3D Li-ion microbatteries, were investigated using finite element modeling with COMSOL Multiphysic®. This work aims to lay the basements for developing a relationship between main limiting factors of Li-ion microbatteries to provide the key points for designing efficient microstructures. Contrary to what was reported in the literature, we demonstrate that electronic conductivity of the electrodes does not play such a major role in limiting the performance of a Li-ion microbattery. We show that the main limiting factor is the diffusion of ions inside the electrodes. It is also demonstrated that geometry and charge applied to the cell (Crate) are intimately related to ionic diffusion in electrodes.