Asymmetric Imides as Electrolyte Additive for Lithium‐Ion Batteries with NCM111 Cathode

Abstract

The synthesis, spectroscopic and electrochemical characterization of Li[N(SiMe 3 )(SO 2 R F )] (R F = CF 3 , n-C 4 F 9 ) as well their behavior as electrolyte additive in lithium ion batteries (LIBs) is reported. The lithium salts were obtained by deprotonation of the corresponding acids HN(SiMe 3 )(SO 2 R F ) with n-butyllithium in n-pentane. The electrochemical investigations suggested poten-tial as additives for LIBs. Thus, NCM111/graphite cells (NCM111 = Li[Ni 0.33 Co 0.33 Mn 0.33 ]O 2 ) with LP57 as electrolyte (LP57 = 1.0 M LiPF 6 in EC/EMC 3 : 7) were built to test the performance. Cells with Li[N(SiMe 3 )(SO 2 R F )] as additives show coulombic efficiencies of over 99.6 %, less capacity fading over 55 cycles and a significantly lower cell impedance built up. in 3 : 7 (wt.%) EC/EMC (LP57, battery grade water content � 50 ppm, BASF®) were used. Additives used were added as weight percentage (0.25 wt.%) relating to the total mass of the electrolyte. All cells were prepared in duplicate. 4 5 6 7 8

Isocyanoethyl Methacrylate (IMA) as a Bifunctional Electrolyte Additive for LiNi0.8Co0.1Mn0.1O2/Graphite Batteries with Enhanced Performance

“…It is an effective way to develop the high specific capacity and high voltage cathode materials to increase the specific energy of LIBs [5] . Among them, the high‐nickel ternary layered oxides LiNi x Co y Mn z O 2 (NCM, 0.5<x, x+y+z=1) have attracted wide attention due to their high specific capacity [6–9] . However, the high‐nickel NCM cathodes have the technical problem to be solved in the existing commercial electrolyte system due to their strong oxidizing ability and poor structural stability [10–12] .…”