Thermally stable, flexible polymer gel electrolytes with high ionic conductivity are prepared by mixing the ionic liquid 1‐butyl‐1‐methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (C4mpyrTFSI), LiTFSI and poly(vinylidene difluoride‐co‐hexafluoropropylene (PVDF‐HFP). FT‐IR and Raman spectroscopy show that an amorphous film is obtained for high (60 %) C4mpyrTFSI contents. Thermogravimetric analysis (TGA) confirms that the polymer gels are stable below ∼300 °C in both nitrogen and air environments. Ionic conductivity of 1.9×10−3 S cm−2 at room temperature is achieved for the 60 % ionic liquid loaded gel. Germanium (Ge) anodes maintain a coulombic efficiency above 95 % after 90 cycles in potential cycling tests with the 60 % C4mpyrTFSI polymer gel.
Ionic liquids are potential alternative electrolytes to the more conventional solid-state options under investigation for future energy storage solutions. This review addresses the utilization of IL electrolytes in energy storage devices, particularly pyrrolidinium-based ILs. These ILs offer favorable properties, such as high ionic conductivity and the potential for high power drain, low volatility and wide electrochemical stability windows (ESW). The cation/anion combination utilized significantly influences their physical and electrochemical properties, therefore a thorough discussion of different combinations is outlined. Compatibility with a wide array of cathode and anode materials such as LFP, V2O5, Ge and Sn is exhibited, whereby thin-films and nanostructured materials are investigated for micro energy applications. Polymer gel electrolytes suitable for layer-by-layer fabrication are discussed for the various pyrrolidinium cations, and their compatibility with electrode materials assessed. Recent advancements regarding the modification of typical cations such a 1-butyl-1-methylpyrrolidinium, to produce ether-functionalized or symmetrical cations is discussed.
High rate and long cycle life performance for electrodeposited, binder‐free V2O5 thin film cathodes and lithium metal anodes is described using liquid and polymer gel electrolytes of the pyrrolidinium based (C4mpyrTFSI) ionic liquid (IL). Sharp well‐defined voltammetric peaks typically seen with nanostructured V2O5 materials in organic electrolytes, support the fast kinetics observed. The addition of vinylene carbonate (VC) stabilises the electrolyte interface leading to higher electrode capacities than for the additive‐free electrolyte, ∼120 versus ∼90 mAh g−1 at 0.75 C. Polymer gel electrolytes based on the IL yield similar electrode capacities, coulombic efficiencies and high rate performances without the VC‐additive. The polymer gel option delivers the better long‐term stability up to 400 cycles with lithium metal anodes with minimal capacity fade at elevated charge and discharge rates up to 5 C.
Purpose: Ramucirumab is an effective treatment for patients with advanced hepatocellular carcinoma (aHCC) and baseline alpha-fetoprotein (AFP) ≥400 ng/mL. We aimed to identify prognostic and predictive factors of response to ramucirumab in patients with aHCC with AFP ≥400 ng/mL from the phase III REACH and REACH-2 randomized trials. Patients and Methods: Patients with aHCC, Child-Pugh class A with prior sorafenib treatment were randomized in REACH and REACH-2 (ramucirumab 8 mg/kg or placebo, biweekly). Meta-analysis of individual patient-level data (pooled population) from REACH (AFP ≥400 ng/mL) and REACH-2 was performed. A drug exposure analysis was conducted for those with evaluable pharmacokinetic data. To identify potential prognostic factors for overall survival (OS), multivariate analyses were performed using a Cox proportional hazards regression model. To define predictors of ramucirumab benefit, subgroup-by-treatment interaction terms were evaluated. Results: Of 542 patients (316 ramucirumab, 226 placebo) analyzed, eight variables had independent prognostic value associated with poor outcome (geographical region, Eastern Cooperative Oncology Group performance score ≥1, AFP >1,000 ng/mL, Child-Pugh >A5, extrahepatic spread, high neutrophil-to-lymphocyte ratio, high alkaline phosphatase and aspartate aminotransferase). Ramucirumab survival benefit was present across all subgroups, including patients with very aggressive HCC [above median AFP; HR: 0.64; 95% confidence interval (CI): 0.49–0.84] and nonviral aHCC (HR: 0.56; 95% CI: 0.40–0.79). While no baseline factor was predictive of a differential OS benefit with ramucirumab, analyses demonstrated an association between high drug exposure, treatment-emergent hypertension (grade ≥3), and increased ramucirumab benefit. Conclusions: Ramucirumab provided a survival benefit irrespective of baseline prognostic covariates, and this benefit was greatest in patients with high ramucirumab drug exposure and/or those with treatment-related hypertension.
Electrode and Electrolyte Materials for Thin Film Microbatteries, Aaron O’Donoghue, Louise McGrath, Ian Povey and James Rohan In this work we assess the electrochemical performance of electrodeposited, binder-free V2O5 thin films with Li metal anodes in liquid and polymer gel electrolytes based on a pyrrolidinium based ionic liquid (C4mpyrTFSI). Coulombic efficiencies >99%, with electrode capacities >120 mAh g-1 are obtained in cyclic voltammetry analysis of crystalline V2O5 with C4mpyr-based Ionic liquid (IL) electrolytes. A polymer gel electrolyte suited to layer by layer microbattery fabrication was synthesised and tested with the crystalline V2O5 and gave large electrode capacities at a relatively high rate (110 mAh g-1 at 2 C) similar to those obtained in liquid electrolytes. Stable long-term cycling (up to 400 cycles) is obtained with Li metal anodes without capacity fade or short circuits developing in either the VC containing IL or the polymer gel analogue. In addition, no V2O5 deterioration is observed with the polymer gel electrolyte as the capacity recovered to ~125 mAh g-1 after cycling at 5 C. Furthermore, we assess surface modification of V2O5 by depositing 3nm Al2O3 via ALD which has been shown to improve the charge-discharge kinetics of oxide electrode materials. Coulombic efficiencies >99%, with peak electrode capacities >120 mAh g-1 are obtained and long-term cycling stabilities up to 625 cycles. 1) L. M. McGrath and J. F. Rohan, Batteries & Supercaps, 4 (2021) 485 – 492, High rate lithium ion cycling in electrodeposited binder-free thin film vanadium oxide cathodes with lithium metal anodes in ionic liquid and polymer gel analogue electrolytes. 2) L. M. McGrath and J. F. Rohan, Molecules, (2020), 25. 6002, Pyrrolidinium containing ionic liquid electrolytes for Li-based batteries. 3) T. Teranishi, Y. Yoshikawa, M. Yoneda, A. Kishimoto, J. Halpin, S. O’Brien, M. Modreanu and I. M. Povey, (2018), ACS Applied Energy Materials, 1(7), pp. 3277-3282, Aluminum Interdiffusion into LiCoO2 Using Atomic Layer Deposition for High Rate Lithium Ion Batteries. Figure 1: Charge/Discharge capacity of 3nm Al2O3 coated V2O5 vs Li foil in 1M LiPF6 in EC:DEC (1:1) Figure 1
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