Subcategory: Materials Science
Room: Exhibit Hall A
Briah Bailey - Claflin University
Co-Author(s): Dr. Nian Liu, Georgia Institute of Technology, GA; Tianqi Hao, Georgia Institute of Technology, GA
In lithium-ion based batteries, charge and discharge is traditionally accomplished via a liquid electrolytic solution transporting lithium ions between the positive and negative electrode. Despite their effectiveness in moving lithium ions and a notable ionic conductivity of 10-3 S/cm, liquid electrolytes have two main problems affecting their overall usability. The first disadvantage is that of a flammability risk which is a byproduct of alkyl carbonates included in the liquid electrolytic solution. This causes a safety concern as lithium batteries are used in cellular devices and overheating of these devices could lead to them igniting and harming users. The second disadvantage, dendrite production, occurs during recharging where lithium ions form deposits of metal inside the battery that can grow to form dendrites. If the dendrites grow large enough to reach the cathode in a battery, premature short circuiting of the battery can occur and negatively affect its lifetime. These main problems have led to the introduction of solid-state electrolytes (SSEs). SSEs are projected to replace the flammable liquid electrolytic solution as well as only allow lithium ions to exit the electrolyte at certain locations. This specificity will decrease the risk of metal deposits leading to dendrite production thus decreasing the risk of premature short circuiting. In this study, the effects of specific materials on the ionic conductivity and physical stability of the superionic lithium tin phosphorous sulfide (LSPS) are examined. These materials include polystyrene-block-poly (ethylene-ran-butylene)-block-polystyrene, polyethylene glycol, and toluene. Polystyrene-block-poly (ethylene-ran-butylene)-block-polystyrene proved to be a promising candidate due to its precedence when combined with anion exchange membranes to produce separators with high chloride ion conductivity. Polyethylene glycol proved to be a promising candidate due the precedence of polyethylene oxides, when combined with lithium-ion conducting materials, producing solid-state cells with impressive rate capability and cycling performance. The effects of combining these materials with LSPS were examined via Electrochemical Impedance Spectroscopy (EIS) where the internal resistance of the battery is measured. A Nyquist Plot was used to illustrate the accompanying EIS curve for each sample. This resulted in an ionic conductivity of 1.11?10-3 S/cm which is a desired conductivity when comparing it to liquid electrolytes and pure LSPS. The Liu lab will continue testing this combination of materials in adverse conditions to investigate its full capabilities.
Funder Acknowledgement(s): I would like to thank the National Science Foundation (NSF) for funding this experience through Grant No. EEC-1757579
Faculty Advisor: Uruthira Kalapathy, email@example.com
Role: I conducted a literature study in order to find materials that would aid in achieving the objective. I then conducted the trials that tested the combinations of materials to test their effectiveness.