Elucidating the Impact of Electrostatic Interactions and Number of Layers on the Mechanisms of Ion Intercalation on Graphene Electrodes

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

Non-Technical Abstract Graphene is an atomically-thin material with emerging electrochemical properties. With the support of the Solid State and Materials Chemistry program, this project studies the impact of its thickness, and the unique materials interactions it enables, on graphene's ability for inserting ions into its structure for applications in electrical energy storage. The scientific impact of this project consists of generating new knowledge that enables the use of simple chemical effects to improve the energy density and stability of battery electrodes. The integrated research, educational and outreach plan addresses learning opportunities for undergraduate and K-12 students. Activities include the modernization of electrochemical instruction and its diffusion through social media, direct laboratory instruction on energy materials through the "electrochemical bootcamp," and outreach activities organized through student organizations. The research team makes use of its identification with the Hispanic population and research group diversity to make an impact in the education, inclusion and retention of underrepresented groups in scientific disciplines. These groups will be exposed to cutting-edge science, using state-of-the-art characterization facilities and advanced computational tools. Technical Abstract The research activity aims at elucidating the impact of graphene's atomic thickness in determining the mechanisms of ion intercalation, and to explore how native and external electrostatic interactions across its thin bulk modify the energetics and rate of intercalation processes. This project contemplates the following goals and approaches: (1) implementing the first electrochemical systematic study of non-aqueous ion intercalation on well-defined graphene electrodes by controlling the number of layers and interfacial electrostatic interactions via micro- and nanofabrication, (2) using in situ neutron reflectometry, transmission electron microscopy, and electrochemical microscopy methods to yield new insights into the intercalation mechanisms of alkaline ions on few layer graphene and the effects of surface modifications, and (3) using density functional theory for understanding quantitatively the energetic components of the electrostatic and electronic interactions and its coupling to innovative force field terms. The knowledge generated by this activity enables the use of simple electrostatic effects for tuning the energetics of ion insertion, potentially improving conditions for electrical energy storage, and establishing broad correlations between electrostatic effects and ionic interfacial and bulk reaction mechanisms that are extendable to other 2D-materials.