Li-Air batteries are electrochemical cells which typically consist of a lithium metal anode and a carbon cathode known as the “air” electrode due to the utilization of oxygen as a reactant. Theoretically, Li-Air batteries have the highest specific energy density among batteries of about 3500 Wh kg-1 (including the mass of the cathodic product). This allows Li-Air batteries to store 5 to 10 times as much energy when compared to current state-of-the-art LIBs. Lithium ions and oxygen react at the cathode during discharge to form lithium peroxide (Li2O2). The focus of this work is on designing hierarchical porous carbon materials with well-defined geometries to be used as cathodes. The utilization of hierarchical porous materials as cathodes could offer several advantages which we aim to verify. Namely, the high surface area offers a higher interfacial contact between the electrode and the electrolyte resulting in higher capacity. Moreover, the presence of wider voids in the form of mesopores and macropores offers transport “highways” for faster charge and molecular transport. Most importantly however, the mesopores offer the possibility of discharge product (Li2O2) storage without clogging ensuring continuous oxygen transport to the reaction centers and reducing passivation. Designing hierarchical carbon with high surface area, high electrical conductivity and low cost could transform energy storage scenario if a practical device could be realized. We also target tuning the electrocatalytic activity of the cathodes for oxygen reduction and oxygen evolution reactions.
This work involves the synthesis of carbon materials with controlled porosity and added electroactivity and testing those as cathodes in Li-O2 batteries to understand the relationship between structure and performance. Students are expected to assist in materials preparation and testing.
Students should have background in either chemical engineering or materials science. They should attend to lab regularly at the times agreed upon. They should not disclose any confidential information outside the team.