9 - Electrolytes for lithium–sulfur batteries

Abstract

The Li–sulfur (Li–S) battery has received immense interest due to its high theoretical specific capacity (1672mAhg−1) and excellent energy density (2600Whkg−1). Critical issues like poor electronic and ionic conductivities, significant volume expansion during cycling, and polysulfide shuttling impede the successive growth of Li–S batteries. These persistent challenges have led to the optimization and modification of the present liquid, polymer, and inorganic electrolytes and the exploration of novel electrolyte materials. This chapter overviews electrolyte development for Li–S batteries. Conventional organic and ionic-liquid electrolytes conductivity comprising various solvents, salts, and additives emphasize improving interfacial architectures and ionic. Polymer electrolytes address the remedies of liquid electrolytes such as safety, suppression of polysulfide shuttling by modifying solid polymer electrolytes into the gel and composite polymer electrolyte. Inorganic solid electrolytes dominate the prevailing liquid and polymer electrolytes owing to advantages of nonflammability, leakage-free, wide potential window, and alleviation of polysulfide migration. Still, some major challenges include high solubility of liquid electrolytes toward polysulfide, a low ion-transfer number, the poor mechanical stability of gel electrolytes, and the high electrode–electrolyte interfacial resistance of inorganic electrolyte require advanced interfacial engineering between electrolyte and electrode components of Li–S batteries. The overall progress of ongoing research, critical challenges, and future outlook of electrolytes for Li–S batteries are discussed deliberately in this chapter.