Hybrid Hairy Nanoparticle Electrolytes Stabilizing Lithium Metal Batteries

Rechargeable batteries comprising an energetic metal (e.g., Li, Na, Al) at the anode provide unparalleled opportunities for-increasing the energy stored in electrochemical cells on either a unit mass or volume basis. A major problem that has hindered development of such cells for the last four decades concerns the electrochemical and mechanical instability of the interface between energetic metals and ion conducting organic liquid electrolytes. This study reports that hybrid electrolytes created by blending low volatility liquids with a bidisperse mixture of hairy nanoparticles provide multiple attractive attributes for engineering electrolytes that are stable in the presence of reactive metals and at high charge potentials. Specifically, we report that such hybrid electrolytes exhibit exceptionally high voltage stability (>7 V vs Li/Li+) over extended times; protect Li metal anodes by forming a particle rich coating on the electrode that allows stable, long-term cycling of the anode at high columbic efficiency; and manifest low bulk and interfacial resistance at room temperature, which enables stable cycling of Li/LiFePO4 half cells at a C/3 rate. We also investigate connections between particle curvature and ion transport in the bulk and at interfaces in such bidisperse hybrid electrolytes.