Anodic Stabilities of Various Metals as the Current Collector in High Concentration Electrolytes for Lithium Batteries

Abstract

Lithium bis(fluorosulfonyl)amide (LiFSI)-based electrolytes not only deliver improved ionic conductivity, but also provide high thermal stability and water tolerance. However, the notorious corrosion of sulfonamide anions against aluminum (Al) current collector restricts their application. High concentration electrolytes (HCEs) have been proposed as alternative electrolytes for lithium batteries owning to their merits of good electrochemical performance and less flammability. Although HCEs have been proved stable to many alkaline cathodes and anodes in the past reports, their compatibility with other battery components, such as the current collector, has not been clearly reported. Herein, electrochemical stabilities of various metals in LiFSI/dimethyl carbonate (DMC) electrolytes were characterized by linear sweep voltammetry and cyclic voltammogram. According to results, when the concentration of the LiFSI/DMC electrolyte is higher than 1:3 (salt/solvent) by molar for Al, and 1:1.2 for titanium (Ti) and stainless steel (SS304), the three materials can be used as the cathode current collector or the other battery components. Moreover, Al that exhibits the best electrochemical stability is still the most ideal current collector compared to other metals. Notably, in the LiFSI:DMC (1:1.5) electrolyte with an Al current collector, stable battery performance with a remaining capacity of 98.8% after 50 cycles can be obtained.