High Charging Voltage Stable and Air Atmosphere Stable Li–O₂ Batteries with an Electrolyte Based on Succinonitrile and In Situ Artificial SEI Construction

One experiment in this study utilized the plasticizer succinonitrile and lithium salt LiTFSI to directly create an ionic liquid electrolyte, with an artificial solid electrolyte interface layer generated using fluoroethylene carbonate. The typical electrolyte exhibited an ionic conductivity of 10^–3 S cm^–1 at room temperature and an electrochemical window of up to 5.3 V based on electrochemical impedance spectroscopy and linear sweep voltammetry tests. This electrolyte system effectively addresses the issues of decomposition and deterioration of traditional organic electrolytes in Li–O₂ batteries at high voltages (over 4.5 V), as well as the problem of direct oxidation of the anode caused by oxygen shuttling, thereby greatly improving the lifespan of Li–O₂ batteries. Additionally, the electrolyte’s low volatility and flame retardancy allowed for reliable operation of the battery in an air atmosphere. A Li–O₂ battery assembled with the novel electrolyte was capable of cycling in a pure oxygen atmosphere for more than 1000 cycles at a capacity density of 200 mA h g^–1 and over 150 cycles at 500 mA h g^–1. Even when connected to ambient air without an additional oxygen selective membrane (OSM), the battery can still cycle continuously for more than 350 and 150 cycles at these two kinds of capacity density.