Electronic Structure Calculations and Synergistic Experimental Work in the Nanostructures for Electrical Energy Storage (NEES) Energy Frontier Research Center

In this presentation, we will review computational effort and synergistic experimental activities in the Nanostructures for Electrical Energy Storage (NEES) Energy Frontier Research Center, and discuss future research directions.  Interfaces and interphases constitute a main theme of our research. Nanoscale structures exhibit enhanced surface areas, and fundamental understanding and smart design of interfaces can help exploit their kinetic advantages while mitigating undesirable parasitic reactions. Thus electrochemical reactions responsible for liquid electrolyte degradation are examined using both large scale ab initio molecular dynamics (AIMD) simulations and complementary ultrahigh vacuum (UHV) measurements. Electrolyte decomposition on lithium peroxide surfaces, a key obstacle in Li-air battery implementation, is examined using analytical/spectroscopic techniques and DFT calculations. Artificial "solid electrolyte interphase" are deposited on amorphous carbon electrodes via atomic layer deposition (ALD) processes, and its electrode-passivating property is characterized by microgravimetric measurements and modelled using DFT calculations coupled with Marcus Theory constructions. This ALD study highlights a second key theme in our research: that necessary fundamental science, computational- and nano-electrochemistry advances emerge naturally in the ostensibly "applied" field of energy storage. We will discuss other examples of method development, such as rigorous voltage calibration in AIMD/DFT calculations, and measurement/control of minute currents associated with single nanowires. Going forward, our new computational approaches will be applied to model solid-solid interfaces pertinent to solid electrolytes, artificially-coated, nanostructured interfaces, and electrode degradation studies.

This work was supported by Nanostructures for Electrical Energy Storage (NEES), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under award no. DESC0001160.  Sandia National Laboratories is a multiprogram laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corpo ration, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.