Anion Redox in Amorphous Transition Metal Sulfides
Abstract
Battery electrode materials are based traditionally on cationic redox processes with 3d transition metals being the most widely investigated. The anions that make up the rest of the material have generally been considered inactive and do not contribute to energystorage. Thus, utilizing redox processes of anions can lead to a potentially large increase in Li-ion battery capacity and energy density, helping to guide the development of next generation Li-ion battery materials. The overarching objective of the research isto use amorphous transition metal sulfides as the basis for obtaining electrode materials which exhibit both cationic and anionic redox. As our initial studies show, amorphous materials benefit from facile bond stretching and overall structural flexibility whichcan be traced to the greater free volume of an amorphous environment. The open architecture of the amorphous system enables the metal-ion coordination to change, which is likely to be a critical feature for the S-S bond breaking and formation processes which are involved in charge storage. To realize this goal, the research will address several fundamental questions regarding amorphous transition metal sulfides. This includes the role of covalency in achieving anion redox, the importance of short-range order in influencing redox reactions and Li-ion diffusion, and identifying compositions which exhibit the highest levels of anion redox. Another objective is to better understand the reasons that amorphous and crystalline transition metal sulfides with the same nominal composition exhibit different redox properties. The proposed research on amorphous transition metal sulfides is intended to be a coordinated program which combines synthesis, electrochemical characterization, synchrotron XAS and computational simulations. By having a critical mass of individual investigators with complementary strengths, we will be able to obtain fundamental understanding of amorphous transition metal sulfides and assess their ability to achieve significantly greater energy density through the combination of anion and cation redox processes. We expect the outcome of this project to not only provide a detailed understanding of anionic redox but also to identify compositions and charge storage mechanisms which lead to high performance battery materials. The potential impact ofthis research on the DoD is that it is directed at identifying new electrochemical materials aimed at improving lithium-ion and sodium-ion battery performance.Approved for Public Release
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 24, 2023
- Source ID
- N000142312667
Entities
People
- Bruce Dunn
Organizations
- Office of Naval Research
- United States Navy
- University of California, Los Angeles