| 1. |
- De La Fuente Durán, Ana, et al.
(författare)
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Origins of hydrogen peroxide selectivity during oxygen reduction on organic mixed ionic-electronic conducting polymers
- 2023
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Ingår i: Energy and Environmental Sciences. - 1754-5692 .- 1754-5706. ; 16:11, s. 5409-5422
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Tidskriftsartikel (refereegranskat)abstract
- Electrochemical reduction of atmospheric oxygen provides carbon emission-free pathways for the generation of electricity from chemical fuels and for the distributed production of green chemical oxidants like hydrogen peroxide. Recently, organic mixed ionic-electronic conducting polymers (OMIECs) have been reported as a new class of active electrode materials for the oxygen reduction reaction. This work sets out to identify the operative oxygen reduction mechanism of OMIECs through a multi-faceted experimental and theoretical approach. Using a combination of pH-dependent electrochemical characterization, operando UV-Vis and Raman spectroscopy, and ab initio calculations, we find that the n-type OMIEC, p(NDI-T2 P75), displays pH-dependent activity for the selective reduction of oxygen to the 2-electron hydrogen peroxide product. We use microkinetic simulations of the electrochemical behavior to rationalize our experimental observations through a polaron-mediated, non-adsorptive pathway involving chemical reduction of oxygen to the 1-electron superoxide intermediate followed by pH-dependent catalytic disproportionation to hydrogen peroxide. Finally, this pathway is applied to understand the experimental oxygen reduction reactivity across several n- and p-type OMIECs.
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| 2. |
- Baeumer, Christoph, et al.
(författare)
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Tuning electrochemically driven surface transformation in atomically flat LaNiO3 thin films for enhanced water electrolysis
- 2021
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Ingår i: Nature Materials. - : Springer Science and Business Media LLC. - 1476-1122 .- 1476-4660. ; 20:5, s. 674-682
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Tidskriftsartikel (refereegranskat)abstract
- Structure–activity relationships built on descriptors of bulk and bulk-terminated surfaces are the basis for the rational design of electrocatalysts. However, electrochemically driven surface transformations complicate the identification of such descriptors. Here we demonstrate how the as-prepared surface composition of (001)-terminated LaNiO3 epitaxial thin films dictates the surface transformation and the electrocatalytic activity for the oxygen evolution reaction. Specifically, the Ni termination (in the as-prepared state) is considerably more active than the La termination, with overpotential differences of up to 150 mV. A combined electrochemical, spectroscopic and density-functional theory investigation suggests that this activity trend originates from a thermodynamically stable, disordered NiO2 surface layer that forms during the operation of Ni-terminated surfaces, which is kinetically inaccessible when starting with a La termination. Our work thus demonstrates the tunability of surface transformation pathways by modifying a single atomic layer at the surface and that active surface phases only develop for select as-synthesized surface terminations.
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| 3. |
- Pham, Phuong V., et al.
(författare)
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Transfer of 2D Films: From Imperfection to Perfection
- 2024
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Ingår i: ACS Nano. - 1936-086X .- 1936-0851. ; 18:23, s. 14841-14876
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Forskningsöversikt (refereegranskat)abstract
- Atomically thin 2D films and their van der Waals heterostructures have demonstrated immense potential for breakthroughs and innovations in science and technology. Integrating 2D films into electronics and optoelectronics devices and their applications in electronics and optoelectronics can lead to improve device efficiencies and tunability. Consequently, there has been steady progress in large-area 2D films for both front- and back-end technologies, with a keen interest in optimizing different growth and synthetic techniques. Parallelly, a significant amount of attention has been directed toward efficient transfer techniques of 2D films on different substrates. Current methods for synthesizing 2D films often involve high-temperature synthesis, precursors, and growth stimulants with highly chemical reactivity. This limitation hinders the widespread applications of 2D films. As a result, reports concerning transfer strategies of 2D films from bare substrates to target substrates have proliferated, showcasing varying degrees of cleanliness, surface damage, and material uniformity. This review aims to evaluate, discuss, and provide an overview of the most advanced transfer methods to date, encompassing wet, dry, and quasi-dry transfer methods. The processes, mechanisms, and pros and cons of each transfer method are critically summarized. Furthermore, we discuss the feasibility of these 2D film transfer methods, concerning their applications in devices and various technology platforms.
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| 4. |
- Zhao, Yun, et al.
(författare)
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Precise separation of spent lithium-ion cells in water without discharging for recycling
- 2022
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Ingår i: Energy Storage Materials. - : Elsevier. - 2405-8289 .- 2405-8297. ; 45, s. 1092-1099
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Tidskriftsartikel (refereegranskat)abstract
- New methods for recycling lithium-ion batteries (LIBs) are needed because traditional recycling methods are based on battery pulverization, which requires pre-treatment of tedious and non-eco-friendly discharging and results in low efficiency and high waste generation in post-treatment. Separating the components of recycled LIB cells followed by reuse or conversion of individual components could minimize material cross-contamination while avoiding excessive consumption of energy and chemicals. However, disposing of charged LIB cells is hazardous due to the high reactivity of lithiated graphite towards cathode materials and air, and the toxicity and flammability of the electrolytes. Here we demonstrate that the disassembly of charged jellyroll LIB cells in water with a single main step reveals no emissions from the cells and near perfect recycling efficiencies that exceed the targets of the US Department of Energy and Batteries Europe. The precise non-destructive mechanical method separates the components from jellyroll cell in water, avoiding both uncontrollable reactions from the anode and burning of the electrolyte, while allowing only a limited fraction of the anode lithium to react with water. Recycling in this way allows the recovery of materials with a value of ∼7.14 $ kg−1 cell, which is higher than that of physical separation (∼5.40 $ kg−1 cell) and much greater than the overall revenue achieved using element extraction methods (<1.00 $ kg−1 cell). The precise separation method could thus facilitate the establishment of a circular economy within the LIB industry and build a strong bridge between academia and the battery recycling industry.
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