Novel Electrolytes and Electrolyte Additives for Metal-Ion and Metal-Air Batteries: A Case Study of Acetonitrile and LiCTFSI

Acetonitrile (AN) as an electrolyte solvent enhances ionic conductivity, and its unique cation solvation affects the transfer kinetics. This chapter provides an exploration of AN’s role, emphasizing its impact on electrolyte functionality. A significant aspect highlighted is the meticulous selection of electrode protection additives in AN-based electrolytes, a critical determinant for their usability. These additives are strategically chosen to undergo reductive decomposition on the negative electrode in metal-ion batteries, effectively preventing repetitive electrolyte decomposition. The chapter further investigates the durability of AN-containing electrolytes featuring low or moderate concentrations of lithium salt using electrochemical methods. This investigation serves to illustrate the enhanced battery performance resulting from the heightened ionic conductivity of the electrolyte. Lithium 4,4,5,5-tetrafluoro-1,3,2-dithiazolidine-1,1,3,3-tetraoxide (LiCTFSI), is a promising lithium salt for usage in lithium-ion battery electrolytes because it does not cause corrosion (anodic dissolution) of the aluminum current collector below 5.0 V vs. Li/Li+. This chapter also provides an overview of LiCTFSI, delving into its unique characteristics and properties. Additionally, the chapter explores the synthetic conditions of LiCTFSI and examines the impact of impurities present in LiCTFSI on battery performance.