Investigating the Conductivity of Lithium-Ion Batteries Across Porous Thin-Films Through the Manipulation of Electrolyte Ion-Transport Rates

Understanding the conductivity of battery cells are an important part of determining their worth. Ionic conductivity defines a battery's ability for ions to move through its electrode structures; a higher conductivity allows for more ions to pass through at a given time, improving the capacity at higher discharge rates. As a higher discharge rate means more energy can be pumped out at a given time, high conductivity is sought after in batteries. In most commercial batteries, the conductivity is generally limited by the ion transport within the solid electrode material, where the interior of larger particles is unable to react fully due to the high rate of charge transfer, leading to lower capacities. The use of sintered electrodes reduces this issue, but make it so that the conductivity is then limited by the ability of ions to pass through the electrode; particles that take a longer time to be reached (i.e. farthest away from the anode) will be unable to react, and so reduce the capacity under what is possible. However, manipulating of such electrodes can minimize this issue and result in higher conductivities. In this project the relationship between ionic conductivity and porous thin-films of different thicknesses are explored through electrochemical analysis using electrochemical impedance spectroscopy and current interrupt cycles to determine if such films manage to produce battery cells of reasonable conductivity.