Two-dimensional high-entropy perovskites for electrochemical energy conversion
Abstract
This research project supports investments by the Department of Defense to advance next-generation solid-state electrochemical devices. The project leverages recent advancements in two-dimensional (2D) materials and high entropy perovskite oxides (HEPs) to pioneer new materials for electrocatalysis. While most previous work on 2D materials has centered on layered, generally covalently-bonded materials held together by weak van der Waals (vdW) forces, our team has identified inexpensive and robust synthetic routes to produce 2D perovskite oxides despite their lack of vdW layer structuring. Additionally, we plan to exploit entropic stabilization enabled by combining five or more cations in the perovskite lattice. Beyond increased stability, the presence of multiple cations also provides significant diversity of surface or subsurface sites, enhancing catalytic activity and efficiency. These advances open the door to creating highly active, ultra-high surface area catalysts from classes of materials that have not previously been considered candidates for 2D materials exploitation. This research project will establish the fundamental science behind the compositional selection and synthesis of 2D HEP electrocatalysts expected to offer unique morphologies, ultra-high surface area, exceptional stability, and tailored control of surface-site activity and cation selectivity. The overarching objective is to understand the fundamental mechanisms of the assembly of pre-perovskite structures in solution and those governing subsequent structural transformation occurring during the final stages of sol-gel synthesis. Three more objectives guide this project: to synthesize HEP nanosheets that are large area, high quality, and ultrathin; to test candidate 2D HEP oxides for their potential as electrocatalysts; and to use computational screening and synthesis, coupled with direct experimental validation to guide design and discovery of novel HEP systems with high resistance to sulfur poisoning and to carbonaceous species. This latter aim is crucial for enabling the use of these electrocatalysts in DoD-specific applications such as logistics-fueled fuel cells. As such, 2D HEP electrocatalysts will have the potential to dramatically increase the performance and functionality of a range of DoD-relevant electrochemical energy conversion devices including batteries, fuel cells, electrolyzers, and chemical sensors. The research team includes investigators with expertise in materials simulation and modeling, synthesis of nanomaterials, and surface and electrochemical characterization. The research capitalizes on this interdisciplinary expertise to achieve the project objectives by applying a four-part technical approach: computational modeling; synthesis and materials characterization; surface and electrochemical characterization under oxidizing conditions; and surface and electrochemical characterization under reducing conditions. This highly coordinated multi-pronged technical approach is leveraged to develop 2D HEPs and examine their potential for redox reversible electrocatalytic reaction processes. The unique approach of this research will lay the foundation for the scientific understanding and deployment of an exciting new class of materials for electrochemical applications. Furthermore, the foundational knowledge resulting from this project can underpin both current and future scientific and societal needs, e.g., vis-a-vis critical nanomaterials needs for quantum systems, catalysis, energy conversion and storage, and beyond.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 22, 2022
- Source ID
- W911NF2210273
Entities
People
- Ryan Ohayre
Organizations
- Army Contracting Command
- Colorado School of Mines
- United States Army