Functional electrolytes: Study of electrolyte for lithium-ion battery using benzene ring-containing methanesulfonate esters as additives

With the announcement of functional electrolytes in 1999, the concept of adding around 1 to 3 wt% additives to the electrolyte to improve the performance of lithium-ion batteries (LIBs) has become widely used worldwide. In our laboratory, we have been investigating the use of methanesulfonate esters with double or triple bonds as additives to form the solid electrolyte interphase (SEI) of the anode. In this work, we investigated methanesulfonate esters with various substituents introduced into the benzene ring, which have currently not received much attention. As a result, we found that the introduction of a fluorine (F) atom is beneficial, and methanesulfonate esters containing pentafluorobenzene or trifluoromethyl benzene groups show an excellent cycling performance even when added in very low amounts of 0.5 wt% or less.