Effect of water and oxygen traces on the cathodic stability of N-alkyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide

The interface between Au(100) and 1-butyl-3-methyl-imidazolium-bis(trifluoromethylsulfonyl)imide

“…Reference [11] reports a breakdown of this kind of anion at higher negative potentials and an adsorption of its reduction products. However, these alleged decomposition currents could not be observed by using pure and dry ionic liquids [43]. Also for BMITf 2 N, we assume a flat orientation of the BMI + cation layer, which is generated and stabilized by π−π interactions and van-der-Waals forces between the alkyl chains.…”

Reactivity of the Ionic Liquid Pyr14TFSI with Superoxide Radicals Generated from KO2or by Contact of O2with Li7Ti5O12

“…Following this procedure, Figure 3a features the ring currents recorded at various electrode rotation rates at a scan rate of 20 mV s −1 and in a potential range of 1.3 -2.8 V Li , holding the disc electrode at a potential of 1.4 V Li at which the reduction of O 2 to O •− 2 is diffusion-controlled. 22 The ring polarization curves feature reduction and oxidation currents at potentials below and above ≈2 V Li , respectively, which correspond to the reduction of the O 2 in the electrolyte to O 2 oxidation reactions are first-order with respect to the reactants' concentrations, the currents measured at any given potential (i meas,E ) can be related to the corresponding diffusion-limited and kinetic currents (i lim and i kin,E respectively) using the Koutecky-Levich equation: [9] whereby i kin,E corresponds to the current that one would measure if the reactant concentration on the surface of the electrode were to be equal to that in the bulk of the electrolyte, ω is the electrode rotation speed, and B is a constant set by the electrolyte kinematic viscosity, the reactant's diffusivity and concentration, and the RRDE's geometry. 2 -oxidation currents at different ω's reach constant plateaus at ≥2.4 V Li , the ring potential of 2.7 V Li used in our previous work 23 and in all RRDE measurements presented hereafter is more than sufficient to grant the diffusion-controlled collection of superoxide radical at the electrode's ring.…”

“…While Kroon et al 4 and Markevich et al 5 reported the instability of the 1-butyl-1-methylpyrrolidinium cation (Pyr 14 , often also referred to as BMP or BMPyr) employing quantum chemical calculations, GC-MS and FTIR analysis, others observed high cycling stability for lithium plating 6,7 as long as the ionic liquid was sufficiently clean and dry. 8,9 Fortunately, the combination with the bis(trifluoromethanesulfonyl)imide anion (TFSI, also abbreviated as (Tf) 2 N − or NTf 2 ) seems to enhance the stability due to its ability to form a passivating surface film upon electroreduction in the presence of lithium cations, and additionally leads to a desired, relatively low viscosity. 5 All these promising properties make Pyr 14 TFSI not only attractive for Li-ion batteries, but also as an electrolyte solvent for aprotic Liair batteries, which has been the focus of many recent studies due to the high theoretical specific capacity of its oxygen cathode.…”

Catalytic reduction of TFSI-containing ionic liquid in the presence of lithium cations

“…On the other hand, some reports state that no SEI is formed in ultra-pure ionic liquids [12] and that impurities are responsible for triggering the decomposition of ILs [12,13].…”