Passivating Lithium Metal Anode by Anti-Corrosion Concentrated Ether Electrolytes for Longevity of Batteries

Abstract

The continuous parasitic reactions (i.e., corrosion) between lithium (Li) and electrolyte gradually exhaust Li supply, leaving batteries of longevity great challenges. Li corrosion relates to Li deposition morphology and characteristics of solid-electrolyte interphase (SEI). Here, we quantitatively detect the Li corrosion, and structural and chemical features of SEI in typical ether and ester electrolytes with varied concentrations. SEI dissolution exposes Li to electrolyte, and initiates chemical/electrochemical corrosion. Concentrated ether electrolytes designed as anti-corrosion solution promises dense Li deposits and formation of fluorinated-SEI (30 nm), which reduces the exposure of Li, and eliminates the formation of galvanic couple comprising Li anode and copper electrode. Li corrosion is declined by 52% (0.53 versus 1.10 μAh h−1). Therefore, both Li||Li (>4950 hours) and LiFePO4||Li cells (750 cycles) can be stably cycled with greatly extended lifespans. This work reveals the battery failure from perspectives of corrosion science, and provides solutions to batteries with longevity by interdicting corrosion.

Keywords: Lithium corrosion, Solid electrolyte interphase, Concentrated electrolyte, Lithium anode, lithium metal batteries