CAREER: Elucidating the Correlative Interfacial Solvation, Nucleation, and Growth Processes in Battery Electrolytes

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

Electrochemical energy storage, mainly in the form of batteries, is crucial to foster the transition from fossil fuel to renewable energy. The invention of lithium-ion batteries has been paradigm-shifting, finding widespread applications in mobile phones, laptops, electric vehicles, and more. However, the continuous development and improvement of battery technologies is currently facing major challenges, as existing battery chemistries are limited in energy density and safety. The fundamental factors determining such limits are still not well understood. The project will bridge this knowledge gap by using a set of tools to probe the internal processes occurring at anode-electrolyte interfaces. The project will focus on the early stages of the battery cycling process and determine the interfacial electrolyte and passivation layer structure. The insights gained from this project will serve as guiding principles to design novel electrolytes for safer, more powerful, and more durable batteries. Education activities of this project, in synergy with the research efforts, are focused on disseminating knowledge on surface/interface science and renewable energy to the scientific community and the general public through hands-on instrument training, scientific demonstration, mentoring, and teaching. These efforts will strengthen the materials characterization capabilities in the research community, raise the awareness and stimulate interest in clean energy and STEM among K-12 students as well as the general public, and enhance the knowledge of electrochemistry and renewable energy among undergraduate students. In the long term, the research and education activities combined will increase the population of qualified individuals to work in STEM and the energy sector. In lithium-ion batteries, a critical component is the solid-electrolyte interphase (SEI), which is formed at the anode-electrolyte interface during early battery cycles. While significant efforts in the research community have been devoted to characterizing the structure and composition of fully-grown SEIs, their dynamic nucleation and growth process and the underlying mechanism remain largely elusive, which is a major bottleneck preventing the predictive design of electrolytes and SEIs for targeted battery applications. The project will study how the structure of solvation layers (also called electrical double layers) at the anode-electrolyte interface plays a dominant role in the SEI nucleation and growth processes. The project will determine the structure and dynamic evolution processes of the electric double layer (EDL) and SEI by combining in situ surface-enhanced Raman spectroscopy and electrochemical 3D atomic force microscopy (recently developed in the PI’s lab), ex situ methods, and atomistic simulations. One outcome of the project will be a quantified electrolyte-EDL-SEI correlation. Specific objectives include: (I) determining the EDL structure at pristine graphite (anode) surface, (II) unraveling initial SEI nucleation and correlation with EDL, and (III) deciphering the mature SEI structure and its formation mechanism. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.