Charge-discharge Performance of an Ionic Liquid-based Sodium Secondary Battery in a Wide Temperature Range

Abstract

A sodium secondary battery has been constructed by using a nonvolatile and nonflammable Na[FSA]-[C₃C₁pyrr][FSA] (FSA = bis(fluorosulfonyl)amide, C₃C₁pyrr = N-methyl-N-propylpyrrolidinium) ionic liquid, a NaCrO₂ positive electrode and a Na metal negative electrode. The charge-discharge performance is evaluated over a wide temperature range of −20–90°C. It has been demonstrated that the sodium secondary battery has long cycle lives both at a high temperature of 90°C and at a low temperature of 0°C. Thus, the ionic liquid-based sodium secondary battery is expected to be a viable alternative to lithium ion battery for many applications.