Understanding and Designing Reversible Anion-Redox Materials
Abstract
Research problem and objectives: The ability to harness redox processes beyond traditionaltransition metal (TM)-based charge compensation phenomena in Li-ion and Na-ion cathodes willenable significant increases in the energy density of electrochemical energy storage technologies.Anion redox remains poorly understood and is accompanied by irreversibilities and degradationmechanisms that lead to hysteresis, voltage fade and limited cycle life. While most electrodechemistries that exhibit anion redox achieve their excess capacity through structure altering redox(SAR) mechanisms that cause electrode degradation, several electrode chemistries exhibitreversible anion redox with minimal polarization. This points to the likelihood that new cathodechemistries exploiting reversible anion redox can be discovered, designed and optimized and enablesignificant increases in energy density. A fundamental understanding must bedeveloped aboutcompeting anion redox mechanisms to enable the rational design of superior electrode materials.The proposed project will seek to elucidate the mechanisms of reversible anion redox and willdevelop a scientific understanding of the chemical and crystallographic requirements to suppressthe irreversibilities that cause hysteresis, voltage fade and electrode degradation in high-capacityoxide electrodes. The hypothesis-driven project will build on two fundamental insights: (i) thatTM chemistry plays a central role in enabling reversible anion redox, thereby providing guidancein the search for optimal chemistries, and (ii) that crystal structure and TM ordering are crucialin suppressing undesirable SAR processes. The chemically informed design principles will beimplementedto guide the search for materials that enable reversible anion redox.Technical Approach: An integrated theoretical and experimentalapproach will be implementedto elucidate reversible and structure altering anion redox processes and to guide the design of newTM oxides. First-principles statistical mechanics methods will be used to model redox mechanismsand electrochemical processes. Electrochemical and structural characterization techniques will becombined with advanced magnetic resonance (NMR, EPR) and magnetometry studies. A uniquefocus of the project will be to probe charge transfer mechanisms from the perspective of the electronspin as a complement to more traditional X-ray based techniques, and the contextualisation ofexperimental with theoretical data.Anticipated outcome of research if successful: The project will lead to a mechanistic understandingof competing anion-redox mechanisms in TM oxides exhibiting capacity beyond traditionalTM-based charge compensation processses, and to the development of physics and chemistryinformeddesign principles with which new and superior electrode materials can be discovered byrational means. The project will also lead to the discovery of new TM oxides that exhibit reversibleanion redox and to the development of a robust theoretical and experimental framework to studythose and device materials relying on similar chemistries and spin physics.Impact on DoD capabilities: The resulting fundamental scientific understanding will enable therational design of electrode chemistries that significantly increase the energy density of rechargeablebatteries. Rechargeable batteries are a crucial component of contemporary and future DoDtechnologies, be it in transportation, portable electronics or as back-up energy storage units.As an educational institution, UCSB performs fundamental and unclassified research. Any data orinformation developed or provided by UCSB,including but not limited to publications and reports, shall beunclassified fundamental research exempt from dissemination controls or review requirements.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 12, 2023
- Source ID
- N000142312333
Entities
People
- Anton Van der Ven
Organizations
- Office of Naval Research
- United States Navy
- University of California, Santa Barbara