This project investigates how the orientation of the carbon cathode with a single-sided microporous layer (MPL) affects battery performance through electrochemical tests, neutron tomography, and titration experiments. The titration experiment quantitatively assesses the amount of solid product (Li2O2) deposited on the electrode surface. In addition, neutron imaging with a 16 µm voxel resolution provides details on the spatial distribution of the solid product within the porous electrodes. Additionally, the performance impact of two electrolyte solvents, tetra ethylene glycol dimethyl ether (TEGDME) and dimethyl sulfoxide (DMSO), is evaluated when used to soak the carbon cathode. The cathode orientation where the MPL faces toward the electrolyte and separator reaches higher discharge and charge capacities and greater average discharge voltages compared to when the MPL faces away from the separator. Batteries discharged with DMSO as the solvent have a 64.86% decrease on average in discharge capacity compared to batteries using TEGDME as the solvent. Both the titration experiments and neutron imaging confirmed that the amount of solid products exhibits a linear correlation with the discharged capacity. Additionally, electrolytes with a high donor number, such as DMSO, were found to result in a smaller amount of Li2O2 deposited on the electrode surface.
Ma et al. (Sun,) studied this question.