NEXT GENERATION OF SOLID-STATE BATTERIES ELECTROLYTES
Rechargeable lithium-ion batteries have revolutionized the portable electronics industry because of their high energy density and efficiency. They may also prove valuable for a variety of other applications, including electrification of the transport system and grid-scale stationary energy storage. However, they still suffer from several significant safety and reliability issues, many of which are related to the use of electrolytes dissolved in organic solvent. Solid-state electrolytes could resolve all of these problems. However, most candidate materials have much lower ionic conductivity compared to that of liquid electrolytes, which reduces the power density of the cell and limits their practical applications. Prussian Blue analogues have recently demonstrated remarkable electrochemical performance that is enabled by rapid movement of ions through their open-framework crystal structure. The overarching goal of this project is to identify PBAs materials that function as a stable, high-power solid electrolyte for lithium-ion batteries. PBA materials have many tunable properties that affect their electronic and structural characteristics.
PHOSPHOURS ANODES FOR SODIUM-ION BATTERIES
With a specific capacity ten times greater than the state of the art, phosphorous has the potential to serve as an anode material for sodium-ion batteries. Red phosphorous is an inexpensive and readily available allotrope of the element, but the degradation it experiences on cycling severely limits its cycle life. Can we use cheap and scalable preparation methods to control phosphorous' particle size, thus increasing cycle life?
CLEAN ENERGY THROUGH PRUSSIAN BLUE ANALOGUES
Prussian blue analogues (PBAs) are a diverse and versatile family of open-framework crystals. Careful control of the chemistry allows our team to tune the materials' macroscopic properties for targeted applications in energy storage. Batteries made from PBAs have the potential to improve energy density, decrease charging time, or increase the cell's safety profile. Can we design PBAs with tailored materials properties for targeted application?
SYNTHESIS AND CHARACTERIZATION OF IONIC LIQUID ELECTROLYTES
Salts with melting points below room temperature are known as ionic liquids. Their properties are highly desirable for battery electrolytes. They have a wide potential window of (electro)chemical stability; they are completely nonflammable, and therefore safe; and they show promising behavior at forming passivating solid-electrolyte interphases in metal batteries. They are hindered by lower ionic conductivity and high cost. Can we find more facile synthetic routes to synthesize more conductive ionic liquids?
Fluoride ion batteries (FIBs) exhibit among the highest theoretical volumetric energy densities of any lithium or post-lithium ion technology under consideration. This potential capability arises from the coupling of highly dense anode (metal) and cathode (metal fluoride) materials through use of an anionic charge carrier (F-). However, at this incipient stage, the discharge/charge mechanism at both electrodes is still poorly understood; furthermore, the design of a liquid electrolyte system for long-term cycling stability has not been fully realized. We are studying the comprehensive mechanistic evaluation and stable long-term cycling through the use of monodisperse, nanocrystalline metal fluoride cathodes.
At the current rate of CO2 emissions, the world is on track for more than 3 °C warming by the year 2100, with catastrophic consequences to global climate. Hydrogen is among the most promising alternative energy sources to replace traditional fossil fuels. Hydrogen generation from electrochemical water splitting is a viable, carbon neutral alternative to steam reforming. Electrocatalysts make the water-splitting reaction more energy efficient by lowering the activation barrier that must be overcome before the reaction can proceed. Platinum is the most effective and durable electrocatalyst, but it is prohibitively scarce and expensive for mass production of electrolyzers. We are investigating single-atom electrocatalysts in which the monoatomic nature of the active sites not only have maximal atom utilization efficiency (lower cost) but also offer opportunities for tuning reaction rates and selectivities.