Andrew J Allen (Fed)

Control of microstructure, internal dynamics and chemistry is of primary importance in determining the performance and viability of solid oxide fuel cells, hydrogen fuel cells, carbon capture materials, and other systems that advance the hydrogen economy, promote US energy independence, or simply advance the Nation’s industry, e.g., through Additive Manufacturing.  The relevant scale range for void and phase microstructure (e.g. interfacial morphology, sintering or annealing), as well as for chemical site reactivity (e.g., combustion, reforming, corrosion) extends from the micrometer down to the sub-nanometer scale regime.  Our goal is to develop in operando measurement methods to quantify full three-dimensional void and phase microstructures and dynamics, including changes during service life and dependence on processing conditions.  These issues apply, e.g., to the electrodes and electrolyte of a SOFC; to the interfaces between them; and to any separate fuel-reforming hydrogen storage, or carbon dioxide capture material, where the microstructure must be related to the reaction site kinetics and to changes in site reactivity during service life.  This opportunity will address these interconnected issues by utilizing unique instrumentation, developed by NIST and its collaborators, and located at the Advanced Photon Source, the National Synchrotron Light Source II, and the NIST Center for Neutron Research. Opportunities exist for investigating novel energy materials and devices including batteries, solid oxide fuel cells, energy harvesting devices, photovoltaics, and additive manufactured components.

Many industrial processes generate CO₂ as a by-product, which is released to the atmosphere and contributes to global warming.  Clean, low-CO₂ emission technology, which requires carbon capture (CO₂ removal from flue gas by solid-state sorbents), is critical to meet our Nation’s energy and manufacturing needs in an environmentally sustainable manner.  Similarly, CO₂ adsorption in shale minerals during enhanced oil and gas recovery will also play a critical role.  Low CO₂ emission technology depends on transient gas/solid material interactions.  Such interactions cannot be inferred from initial or final state materials property measurements such as sorbent microstructure, but must be measured in situ during the sorption or release process.  This project focuses on the design, construction, and application of a suite of in situ measurement platforms for use with NIST’s state-of-the-art neutron and synchrotron X-ray scattering facilities, capable of interrogating critical carbon capture properties across the range of candidate CO₂ sorbent solid materials, as well as oil and gas shales.  Measurements using the platform suite will focus on in situ determination of changes in structure, microstructure, atomic bonding, and dynamics in sorbent materials during the sorption and release of CO₂ under controlled conditions of temperature, pressure, humidity, and atmosphere.  X-ray or neutron diffraction analysis and thermogravimetric analysis will be carried out in situ with samples that are simultaneously undergoing evolved gas analysis.