The Li–S battery: an investigation of redox shuttle and self-discharge behaviour with LiNO3-containing electrolytes

Abstract

The polysulfide redox shuttle and self-discharge behaviour of lithium–sulfur (Li–S) cells containing the electrolyte additive LiNO₃ has been thoroughly explored by a range of electrochemical and surface analysis techniques on simple Li–S (i.e., not specifically optimised to resist self-discharge) and symmetrical Li–Li cells. Despite the relatively effective passivation of the negative electrode by LiNO₃, fully charged cells self-discharged a quarter of their capacity within 3 days, although in the short-term cells can be recharged without any noticeable capacity loss. The processes governing the rate and reversibility of self-discharge in these cells have been investigated and explained in terms of the reactions of polysulfides occurring at both electrodes during idle conditions.