758716-72-2Relevant articles and documents
Ionic Liquid Functionalized Gel Polymer Electrolytes for Stable Lithium Metal Batteries
Zhou, Tianhong,Zhao, Yan,Choi, Jang Wook,Coskun, Ali
supporting information, p. 22791 - 22796 (2021/09/09)
Metallic lithium (Li) is regarded as the ideal anode material in lithium-ion batteries due to its low electrochemical potential, highest theoretical energy density and low density. There are, however, still significant challenges to be addressed such as Li-dendrite growth and low interfacial stability, which impede the practical application of Li metal anodes. In order to circumvent these shortcomings, herein, we present a gel polymer electrolyte containing imidazolium ionic liquid end groups with a perfluorinated alkyl chain (F-IL) to achieve both high ionic conductivity and Li ion transference number by fundamentally altering the solubility of salt within the gel electrolyte through Lewis-acidic segments in the polymer backbone. Moreover, the presence of F-IL moieties decreased the binding affinity of Li cation towards the glycol chains, enabling a rapid transfer of Li cation within the gel network. These structural features enabled the immobilization of anions on the ionic liquid segments to alleviate the space-charge effect while promoting stronger anion coordination and weaker cation coordination in the Lewis-acidic polymers. Accordingly, we realized a high Li ion conductivity (9.16×10?3 S cm?1) and high Li ion transference number of 0.69 simultaneously, along with a good electrochemical stability up to 4.55 V, while effectively suppressing Li dendrite growth. Moreover, the gel polymer electrolyte exhibited stable cycling performance of the Li|Li symmetric cell of 9 mAh cm?2 for more than 1800 hours and retained 86.7 % of the original capacity after 250 cycles for lithium-sulfur (Li-S) full cell.
Photogenerated lophyl radicals in 1-alkyl-3-vinylimidazolium bis(trifluoromethylsulfonyl)imides
Berdzinski, Stefan,Strehmel, Bernd,Strehmel, Veronika
, p. 714 - 725 (2015/04/14)
1-Alkyl-3-vinylimidazolium bis(trifluoromethylsulfonyl)imides were investigated as a matrix for photogenerated lophyl radicals obtained by irradiation of o-chlorohexaarylbisimidazole (o-Cl-HABI). Photoinduced polymerization of ionic liquid monomers using the photoinitiator system composed of o-Cl-HABI and 3-mercapto-1,2,4-4H-triazole was investigated by photo-DSC. Selected thermal properties and viscosity of these ionic liquid monomers are important to understand the lophyl radical kinetics after exposure. Solvent cage effects and viscosity of the ionic liquid monomers strongly affect radical recombination in the dark. This was investigated at different temperatures. The rate constant for radical recombination (krec) decreases from the methyl to the butyl substituted ionic liquid monomer. This may be attributed to an increasing viscosity with increasing size of the alkyl substituent. However, further increase in the size of the alkyl substituent from a butyl to a heptyl group bound at the imidazolium ion results in an increase of krec although the viscosity does further increase. Therefore, a minimum in krec was found for the butyl substituted ionic liquid monomer. Furthermore, the Eyring parameters indicated a dependence on the chain length of the alkyl substituent bound at the imidazolium ion while the activation energy of the viscous flow only slightly changes. Furthermore, the size of the alkyl substituent bound at the cation of the ionic liquid monomers strongly influences both solvent cage and viscosity, and therefore, the concentration of lophyl radicals during photoinduced generation. Photo-induced polymerization of the ionic liquid monomers is affected by viscosity at low conversion and by vitrification at higher conversion. The latter is important for application of the ionic liquid monomers and the polymers made from them by photoinduced polymerization.
