PNNL

Abstract

High-voltage (>4.0 V) rechargeable lithium (Li) metal batteries face huge obstacles due to the high reactivity of Li metal with traditional organic carbonate electrolytes. It is generally accepted that ether-based electrolytes are unstable above 4.0 V and thus unsuitable for high voltage applications, despite of their good compatibility with Li metal. Here we report a concentrated ether electrolyte that could be used under high voltage up to 4.5 V with the formation of a unique cathode/electrolyte interphase enriched in LiF, which effectively preserves the cathode crystalline structural integrity. Employing this high concentration ether electrolyte, Li metal batteries with a moderately high cathode loading of 1.5 mAh cm-2 can have a capacity retention of 92% after 500 cycles at 4.3 V and demonstrate nearly 100% cycling efficiency even at 4.5 V.