Title: Adiponitrile-LiTFSI solution as alkylcarbonate free electrolyte for LTO/NMC Li-ion batteries,
Abstract: Recently, dinitriles (NC(CH2)nCN) and especially adiponitrile (ADN, n=4) have
attracted the attention as secure electrolyte solvents due to their chemical
stability, high boiling points, high flash points and low vapor pressure. The
good solvating properties of ADN toward lithium salts and its high
electrochemical stability (~ 6V vs. Li/Li+) make it suitable for safer Li-ions
cells without performances loss. In this study, ADN is used as a single
electrolyte solvent with lithium bis(trimethylsulfonyl)imide (LiTFSI). This
electrolyte allows the use of aluminum collectors as almost no corrosion occurs
at voltages up to 4.2 V. Physico-chemical properties of ADN-LiTFSI electrolyte
such as salt dissolution, conductivity and viscosity were determined. The
cycling performances of batteries using Li4Ti5O12 (LTO) as anode and
LiNi1/3Co1/3Mn1/3O2 (NMC) as cathode were determined. The results indicate that
LTO/NMC batteries exhibit excellent rate capabilities with a columbic
efficiency close to 100%. As an example, cells were able to reach a capacity of
165 mAh.g-1 at 0.1C and a capacity retention of more than 98% after 200 cycles
at 0.5C. In addition, electrodes analyses by SEM, XPS and electrochemical
impedance spectroscopy after cycling confirming minimal surface changes of the
electrodes in the studied battery system