Blade-Coatable Hexagonal Boron Nitride Ionogel Electrolytes for Scalable Production of Lithium Metal Batteries
Cory M. Thomas, Woo Jin Hyun, Hsien Cheng Huang, Davy Zeng, Mark C. Hersam
Abstract
Solid-state electrolytes have attracted significant attention for rechargeable lithium-ion batteries due to their potential to enable higher energy density technologies and improve cell safety by removing volatile liquid electrolytes. However, existing solid-state electrolyte materials lack sufficient electrochemical performance or require expensive and time-consuming processing methods that have prevented their wide-scale adoption. Here, a blade-coatable hexagonal boron nitride ionogel electrolyte is introduced that exhibits high room temperature ionic conductivity (>1 mS cm–1), is stable against lithium metal anodes, and can be applied over a wide area in a thin (<40 μm) and crack-free film. Furthermore, this blade-coatable slurry has a tunable viscosity to enable its use in existing battery manufacturing infrastructure. The resulting blade-coated hBN ionogel electrolyte is employed in a lithium metal battery with a LiFePO4 cathode, exhibiting superlative rate capability at room temperature with a 78% capacity retention after 500 cycles at a rate of 1C.