(232d) Electrolyte Design for Beyond Li-Ion Batteries

Batteries with high energy densities (energy stored per mass or volume) are required to electrify transportation and the grid. Lithium metal batteries can double the energy density of current lithium-ion batteries by replacing the graphite anode with a lithium metal anode. However, lithium metal is highly reactive, electrodeposits in a high surface area dendritic morphology, and continuously decomposes the electrolyte. Solid state electrolytes are promising because of nonvolatility and safety, but suffer from high electrode/electrolyte interfacial resistance. In contrast, liquid electrolytes have high ionic conductivities and low interfacial resistance but are volatile and flammable. Here, we develop solvent-free electrolytes that maintain the benefits of nonvolatile solids while enabling an improved electrode/electrolyte interface. We probe the influence of these electrolytes on lithium metal deposition and stripping, interfacial composition, and long term lithium metal cycling. Our work illustrates the importance of new electrolyte classes for next generation lithium-based batteries.