N-methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl)imide (PP13-TFSI) - Novel electrolyte base for Li battery

A few room temperature ionic liquid containing quaternary ammonium cation and imide anion was prepared and electrochemically evaluated with compared the conventional room temperature ionic liquid system with 1-ethyl-3-methylimidazolium cation. Ability as an electrolyte base of lithium battery system was totally explained with the cathodic stability of the salt, however, another properties might also affect. Among the salts studied here, N-methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl)imide is the most promising candidate as the electrolyte base. Li/LiCoO₂ cell containing the salt showed very good performance with a consistent capacity of LiCoO₂ and the Coulombic efficiency at entire cycles of more than 97% at C/10 current rate. When cycled at higher rate (C/2), 85% of the discharge capacity was still retained.