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Item Synthesis and reactivity of α-diazo-β-keto sulfonamides(Georg Thieme Verlag KG, 2024-06-19) Maguire, Anita R.; Judge, Evan; O'Shaughnessy, Keith A.; Lawrence, Simon E.; Collins, Stuart G.; Science Foundation Ireland; Irish Research Council; Higher Education Authority; Synthesis and Solid State Pharmaceutical Centre; European Regional Development FundCopper mediated reactions of α-diazo-β-keto sulfonamides 1 leads to a range of products including the alkyne sulfonamides 5, the enamines 6, and the α-halosulfonamides 7 and 11 with no evidence for intramolecular C–H insertion in any of the reactions, in contrast to the reactivity of the comparable α-diazo-β-keto sulfones. Use of copper(II) triflate (5 mol%) led to isolation of a series of alkyne sulfonamides 5 (up to 12%) and enamines 6 (up to 64%). Use of copper(II) chloride (5 mol%) formed, in addition, the α-halosulfonamides 7; use of stoichiometric amounts of copper(II) chloride/bromide enables facile halogenation of the β-keto sulfonamide to form the α-halosulfonamides 7 and 11 (up to 63%).Item Guanidine functionalized porous SiO2 as heterogeneous catalysts for microwave depolymerization of PET and PLA(Royal Society of Chemistry, 2024-03-06) Casey, Éadaoin; Breen, Rachel; Pareras, Gerard; Rimola, Albert; Holmes, Justin D.; Collins, Gillian; Science Foundation IrelandChemical recycling is an important strategy to tackle the growing global problem of plastic waste pollution. The development of metal-free catalysts for depolymerization of plastics is attractive as it avoids the use of metal salts, which are potentially damaging to the environment. Here we report a metal-free heterogeneous catalyst for the glycolysis of polyethylene terephthalate (PET) and methanolysis of polylactic acid (PLA). The catalysts are synthesized by covalent surface modification of mesoporous silica (SiO2) with guanidine ligands and evaluated under conventional thermal and microwave-assisted heating. A surface bound cyanoguanidine ligand was found to be the best catalyst leading to 100% PET conversion with 80% BHET yield. The nature of the catalyst support material influenced the catalytic performance of the guanidine ligands with porous SiO2 supports outperforming activated carbon in conventional thermal glycolysis, while the opposite trend was observed with microwave assisted glycolysis. Dedicated density functional theory (DFT) computations were performed to simulate the depolymerization processes, obtain the free energy profiles of the reaction mechanisms, and identify the important role of hydrogen bonding in the reaction mechanism.Item 3D printed rechargeable aqueous and non-aqueous lithium-ion batteries: Evolution of design and performance(Electrochemical Society, 2023-12-12) Egorov, Vladimir; Gulzar, Umair; O'Dwyer, Colm; Horizon 2020; European Regional Development Fund; Irish Research Council; Enterprise Ireland; Higher Education AuthorityHere we describe the modeling and design evolution of vat polimerized (Vat-P) stereolithographic apparatus (SLA) 3D printed coin cell-type aqueous and non-aqueous rechargeable lithium-ion batteries, cases and current collectors. We detail the rationale for design evolution that improved performance, handling and assembly of the printed batteries. Some guidance into the modeling, 3D printing process, material choice, chemical and electrochemical stability, assembly, sealing, and performance of 3D printed Li-ion batteries is outlined. 3D printed Li-ion batteries demonstrated promising results in terms of gravimetric capacity, rate capability, and capacity per unit footprint area compared to conventional coin cells in both aqueous and non-aqueous systems. For aqueous cells, the cell level capacity is a factor of 2–3x higher than similar metal coin cells due to the lighter weight and better rate response. We also outline design requirements for a Vat-P printed battery that are compatible with organic carbonate-based electrolytes, where the cell provides 115 mAh g−1 specific capacity using an LiCoO2–graphite chemistry, which is only ∼20% less than the maximum reversible capacity of LCO. Despite the challenges faced in optimizing the design and materials for 3D printed Li-ion batteries, this study provides valuable information for future research and development.Item Surface modification improves spinel LiCoO2 Li-ion battery cathode materials grown by low temperature solvothermal flow reaction(IOP Publishing, 2024-01-29) Zhang, Yan; Gulzar, Umair; Lonergan, Alex; Grant, Alex; Carroll, Aoife; Roy, Ahin; Nicolosi, Valeria; Keene, Tony D.; O’Dwyer, Colm; Horizon 2020; Irish Research Council; Science Foundation IrelandMethods that provide routes to LiCoO2 growth with lower energy requirements from recycled battery cathode ashes are important for sustainable Li-ion battery technology . Here, a low temperature route to a stable, coated spinel-phase LT-LCO material with secondary Co3O4 phase can be achieved at 300 °C directly from the layered double hydroxide [Li2(ox)2][Co5(OH)8] product of solvothermally synthesized LiOH and CoCl2. The low-temperature LiCoO2 materials (known as LT-LCO) consist of spinel-phase LCO and secondary Co3O4 phase. As a cathode in lithium batteries, we used a solution-based method of coating with an ionic conductor LiAlO2 with AlF3 to mitigate sluggish reversible lithiation kinetics and the poor cycling and rate performance of as-synthesized spinel LT-LCO. The coating modification promotes reversible lithium ion transfer and stabilizes the spinel structure.The modified LT-LCO cathode has significantly better overall capacity and rate performance, with a capacity retention of ∼80 mAh g−1 after 150 cycles (factoring the LT-LCO and Co3O4 mass). The initial first cycle coulombic efficiency significantlyimproves to >95%. The data show that even spinel phase LCO grown by this solvothermal route cycles stably with a useful specific capacity and rate response in the voltage range 2.0–4.2 V.Item Real-time nondestructive methods for examining battery electrode materials(American Institute of Physics, 2023-03) Grant, Alex; O'Dwyer, Colm; Irish Research CouncilWith the importance of Li-ion and emerging alternative batteries to our electric future, predicting new sustainable materials, electrolytes, and complete cells that safely provide high performance, long life, and energy dense capability is critically important. Understanding the interface, the microstructure of materials, and the nature of electrolytes and factors that affect or limit long-term performance is key to new battery chemistries, cell form factors, and alternative materials. The electrochemical processes `that cause these changes are also difficult to probe because of their metastability and lifetimes, which can be of nanosecond to sub-nanosecond time domains. Consequently, developing and adapting high-resolution, nondestructive methods to capture these processes proves challenging, requiring state-of-the-art techniques. Recent progress is very promising, where optical spectroscopies, synchrotron radiation techniques, and energy-specific atom probe tomography and microscopy methods are just some of the approaches that are unraveling the true internal behavior of battery cells in real-time. In this review, we overview many of the most promising nondestructive methods developed in recent years to assess battery material properties, interfaces, processes, and reactions under operando conditions similar in electrodes and full cells.