California Institute of Technology
One is the Loneliest Number: Multivalent and Multielectron Processes for Next-Generation Batteries
Rechargeable Li-ion batteries revolutionized energy storage but the fundamental limitations imposed by intercalation chemistry and the cost associated with common components in Li-ion cells drive the need for new, less expensive batteries. The search for these “beyond Li-ion” technologies include systems based on alternative charge storage mechanisms that promise high theoretical energy densities. Our lab focuses on multielectron and multivalent to bypass limitations imposed by conventional intercalation chemistry paradigms while using sustainable elements. I will discuss the electrochemistry Li-rich materials that support multielectron redox, i.e., >1 electron redox per transition metal, with much of the charge compensation localized on the anion. Anion redox causes bonds to form and break, which alters the local structure and has implications on kinetics and reversibility. I will also discuss our efforts in the area of divalent working ions as alternatives to Li-based systems. Divalent working ions like Mg, Ca, and Zn are only exciting as next-generations chemistries if metal anodes are used. Thus, we will discuss the nature of divalent metal deposition and stripping from solution phase electrolytes. The conduction of divalent ions in the solid-state is also a challenge that prevents translation. I will discuss strategies to overcome issues that are commonly presumed to plague divalent ions: high activation energy and low conductivity.