Investigating the Electrode Kinetics of the Li/Li⁺ Couple in a Wide Range of Room Temperature Ionic Liquids at 298 K

Cyclic voltammetry experiments are carried out using a 0.1 M Li + solution in 12 different room temperature ionic liquids (RTILs), [C 4 mpyrr][NTf 2 ], [C 4 dmim][NTf 2 ], [N 2,1,1,3 ][NTf 2 ], [N 6,2,2,2 ][NTf 2 ], [C 4 mim][OTf], [C 4 mpyrr][N(CN) 2 ], [C 2 mim][NTf 2 ], [P 14,6,6,6 ][FAP], [C 4 py][NTf 2 ], [C 4 mim][PF 6 ], [C 4 mim][NTf 2 ], and [N 1,8,8,8 ][OTf], on a Ni microelectrode to investigate the deposition and stripping of lithium from the electrode surface. [C 4 mpyrr][N(CN) 2 ], [C 2 mim][NTf 2 ], [P 14,6,6,6 ][FAP], [C 4 py][NTf 2 ], [C 4 mim][PF 6 ], [C 4 mim][NTf 2 ], and [N 1,8,8,8 ][OTf] did not have a wide enough potential window to observe the deposition and stripping of bulk lithium. In the experimental data recorded for [C 4 mpyrr][NTf 2 ], [C 4 dmim][NTf 2 ], [N 2,1,1,3 ][NTf 2 ], [N 6,2,2,2 ][NTf 2 ], and [C 4 mim][OTf], a single stripping peak for bulk lithium is seen, and kinetic data for the Li/Li + couple are extracted by comparison with computational simulations. The electrochemical rate constant, k 0, is found to have values ranging from (1.3·10 −6 to 1.2·10 −5 ) cm·s −1 . Diffusion coefficients for the Li + ion in these five RTILs are also reported.