Electrolyte and sodium-ion battery containing the electrolyte

Abstract

This invention provides an electrolyte and a sodium-ion battery. The electrolyte comprises a sodium salt, a non-aqueous organic solvent, and additives. The additives include: (a) sodium acesulfame potassium, with the structural formula shown in Formula 1; and (b) an acid anhydride compounds. The electrolyte comprises sodium acesulfame potassium and an acid anhydride compounds. Sodium acesulfame potassium can form a tough, shatter-resistant, and high-temperature resistant interfacial film during the first charge-discharge stage of the battery. However, this interfacial film contains sulfur and nitrogen elements, which easily dissolve in the electrolyte, consuming some of the active sodium to form a new interfacial film, causing gas production and a decrease in the initial coulombic efficiency of the battery. The acid anhydride compounds, due to their high film-forming potential, easily form a dense interfacial film at the negative electrode, effectively mitigating the side reactions of sodium acesulfame potassium in the electrolyte after film formation. Using this electrolyte in a sodium-ion battery can improve the initial coulombic efficiency, high-temperature storage performance, and cycle performance of the sodium-ion battery under high voltage.

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