Electrolyte and electrochemical energy storage device

Abstract

The present disclosure provides an electrolyte and an electrochemical energy storage device, the electrolyte comprises an electrolyte salt and an additive. The additive comprises a sulfonic ester cyclic quaternary ammonium salt and a multinitrile compound. The sulfonic ester cyclic quaternary ammonium salt and the multinitrile compound can form a dense and uniform passive film with high ionic conductivity on a surface of each of the positive electrode film and the negative electrode film, so as to prevent continuous oxidation and reduction reaction from occurring between the electrolyte and the positive electrode film and the negative electrode film and make the electrochemical energy storage device has excellent high temperature cycle performance and high temperature storage performance.

Dependencies are inferred from the claim text.