Kinetic and Thermodynamic Parameters of the Li/Li⁺ Couple in the Room Temperature Ionic Liquid N-Butyl-N-methylpyrrolidinium Bis(trifluoromethylsulfonyl) Imide in the Temperature Range 298−318 K: A Theoretical and Experimental Study Using Pt and Ni Electrodes

Abstract

The Li/Li+ couple is investigated in the room temperature ionic liquid N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, [C4mpyrr][NTf2], at a range of temperatures varying from 298 to 318 K.Experiments are conducted using both nickel and platinum microelectrodes. On nickel, a single stripping peak is observed for the stripping of bulk lithium that allowed thermodynamic and kinetic parameters to be extracted via computational simulation. At 298 K, the electrochemical rate constant (k0) ) 1.2 X 10-5 cms-1, the diffusion coefficient (D) ) 4.5 X 10-8 cm2 s-1, the formal potential (E(f)0 ) -3.26 V versus the Fc/Fc+ reference couple, and the transfer coefficient (alpha) = 0.63. On platinum, multiple stripping peaks are observed due to the stripping of Li-Pt alloys in addition to the stripping of bulk lithium. The ratio of the different stripping peaks is found to change with temperature, indicating that Li-Pt alloys are more thermodynamically stable than pure bulk lithium and platinum.

Correlating Structure and Properties of Super‐Concentrated Electrolyte Solutions: 17O NMR and Electrochemical Characterization

“…0.25 V vs. Li + /Li is related to the bulk stripping process of the alkali metal. In all the investigated electrolytes, the anodic peaks at potentials higher than 0.50 V vs. Li + /Li can be attributed to the oxidation of intermetallic Li−Pt alloys formed during the cathodic scan, as already reported by Wibowo et al . The peak current is related to the diffusion coefficient ( D ) and concentration ( C ) of the redox species at the interphase.…”

An AlCl3 based ionic liquid with a neutral substituted pyridine ligand for electrochemical deposition of aluminum

“…9 shows the cyclic voltammogram of the IL on a platinum working electrode at a scan rate of 100 mV/s. The aluminum deposition started at a potential of À0.16 V vs Al/Al 3+ , and there was a corresponding aluminum stripping peak at 0.35 V. It was noticed that the bulk deposition region showed a characteristic "nucleation loop" where the forward and backward current cross over [35]. The bulk electrolysis was carried out using a polished copper strip as the cathode, spiral aluminum wire as the counter electrode, and straight aluminum wire as the reference electrode.…”

The electrochemistry of lithium in ionic liquid/organic diluent mixtures

“…Lithium ion reduction peaks are well defined for each diluent system with the onset near −3.6 V vs. ref. In each case, the reverse scan is characterised by a main oxidation peak which is complicated by two shoulders, near −2.9 and −2.7 V, in addition to a very small peak at −2.2 V. Compton and coworkers have studied these multiple oxidation peaks (obtained under similar conditions at a Pt electrode in an ionic liquid [25]) and attribute them to the stripping of both lithium metal and different Li-Pt alloys. Based on the high degree of similarity of the responses reported here, we apply the same interpretation.…”