An emerging class of ion-dense electrolytes consisting of complexed lithium cations and weakly basic anions, known as solvate ionic liquids, possess many desirable attributes for lithium-based electrochemical energy storage. In this study, a series of fully zwitterionic (f-ZI) polymer scaffold-supported solvate ionogels are synthesized via UV-initiated free-radical (co)polymerization of two zwitterionic monomers, 2-methacryloyloxyethyl phosphorylcholine (MPC) and sulfobetaine vinylimidazole (SBVI), in situ within the solvate ionic liquid [Li(G4)][TFSI], which is prepared from an equimolar mixture of lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) and tetraglyme (G4). Systematically varying the MPC:SBVI molar ratio within the f-ZI polymer network enables one to widely tune the mechanical properties of the poly(MPC-co-SBVI)-supported solvate ionogel composites. For a fixed polymer content of 20 mol %, gel compressive elastic modulus values are observed to span 2 orders of magnitude, from 23 kPa to 7.3 MPa, while the room temperature ionic conductivity values remain fairly unchanged (between 0.48 and 0.70 mS cm–1). MPC-rich copolymer formulations lead to solvate ionogels that exhibit substantial plastic deformation, exceeding 200% tensile strain prior to failure, and Li-ion transference numbers as high as 0.60, which represents a 5-fold increase compared to the neat solvate ionic liquid electrolyte. A 20 mol % poly(MPC-co-SBVI)-supported solvate ionogel having a 3:1 MPC:SBVI molar ratio successfully enables the galvanostatic cycling of a lithium-ion battery prototype for 100 cycles at a rate of C/2, demonstrating the viability of these safer gel electrolytes for lithium-based energy storage devices.
A critical barrier to overcome in the development of solid-state electrolytes for lithium batteries is the trade-off between sacrificing ionic conductivity for enhancement of mechanical stiffness. Here, a physically-crosslinked, polymer-supported gel electrolyte consisting of a lithium salt/ionic liquid solution featuring a fully-zwitterionic (ZI) copolymer network is introduced for rechargeable lithiumbased batteries. The ZI scaffold is synthesized using a 3:1 molar ratio of 2-methacryloyloxyethyl phosphorylcholine and sulfobetaine vinylimidazole, and the total polymer content is varied between This article is protected by copyright. All rights reserved. 2 1.1 -12.5 wt.%. Room temperature ionic conductivity values comparable to the base liquid electrolyte (~1 mS cm -1 ) are achieved in ZI copolymer-supported gels that display compressive elastic moduli as large as 14.3 MPa due to ZI dipole-dipole crosslinks. Spectroscopic characterization suggests a change in the Li + coordination shell upon addition of the zwitterions, indicative of strong Li +… ZI group interactions. Li + transference number measurements reveal an increase in Li + conductivity within a ZI gel electrolyte ( nearly doubles). ZI gels display enhanced stability against Li metal, dendrite suppression, and suitable charge-discharge performance in a graphite|lithium nickel cobalt manganese oxide (NCM) cell. Fully-ZI polymer networks in nonvolatile, ionic liquid-based electrolytes represent a promising approach toward realizing highly conductive, mechanically rigid gels for lithium battery technologies.introduced for Li-based batteries. The zwitterionic copolymer: (1) disrupts Li + -TFSIcomplexes and(2) forms dipole-dipole crosslinks with itself. This dual functionality promotes a tunable elastic modulus and an increase in Li + conductivity, while demonstrating stability against Li metal and high rate capability in a Li-ion cell.
These findings suggest that the factors (loss of consciousness, creatinine level, hemoglobin level) that are predictive of death may be a reflection of shock in this patient population. Further studies should be directed to optimizing preoperative resuscitation. Patients who have a ruptured abdominal aortic aneurysm should not be denied therapy on the basis of any specific set of preoperative factors.
Laparoscopically assisted AAA repair is technically challenging but feasible. Potential advantages may be early removal of nasogastric suction, shorter intensive care unit and hospital stays, and prompt return to full functional status. The hemodynamic data obtained from the pulmonary artery catheter and transesophageal echocardiogram during pneumoperitoneum suggest that transesophageal echocardiography may be sufficient for evaluation of volume status along with the added benefit of detection of regional wall motion abnormalities and aortic insufficiency. Further refinement in technique and instrumentation will make total laparoscopic AAA repair a reality.
Polymer-supported ionic liquids (ionogels) are emergent, nonvolatile electrolytes for electrochemical energy storage applications. Here, chemical and physical interactions between the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMI TFSI) and three different cross-linked polymer scaffolds with varying chemical functional groups have been investigated in ionogels fabricated via in situ UV-initiated radical polymerization of methyl methacrylate (MMA), 2,2,2-trifluoroethyl methacrylate (TFEMA), or 2-(dimethylamino)ethyl methacrylate (DMAEMA) and a small amount of the cross-linker pentaerythritol tetraacrylate. Experimental findings demonstrate that the chemical functionality of the polymer side groups can significantly affect the degree of ion dissociation within the ionic liquid component of the ionogel and that the fraction of dissociated ions is the dominant factor in determining relative ionic conductivity in these materials, rather than any large differences in ion diffusivity. The MMA-based polymer scaffold exhibits a stronger attractive interaction with EMI TFSI (as evidenced by a higher activation energy of ionic conductivity) compared to the TFEMA- and DMAEMA-based scaffolds, resulting in consistently lower ionic conductivity values for MMA-based ionogels. These results may offer guidance toward the rational selection of future polymer-ionic liquid pairings in order to maximize the fraction of dissociated ions, thereby yielding highly conductive ionogel electrolytes.
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