Seed-mediated atomic-scale reconstruction of silver manganate nanoplates for oxygen reduction towards high-energy aluminum-air flow batteries

Aluminum-air batteries are promising candidates for next-generation high-energy-density storage, but the inherent limitations hinder their practical use. Here, we show that silver nanoparticle-mediated silver manganate nanoplates are a highly active and chemically stable catalyst for oxygen reduction in alkaline media. By means of atomic-resolved transmission electron microscopy, we find that the formation of stripe patterns on the surface of a silver manganate nanoplate originates from the zigzag atomic arrangement of silver and manganese, creating a high concentration of dislocations in the crystal lattice. This structure can provide high electrical conductivity with low electrode resistance and abundant active sites for ion adsorption. The catalyst exhibits outstanding performance in a flow-based aluminum-air battery, demonstrating high gravimetric and volumetric energy densities of similar to 2552 Wh kg(Al)(-1) and similar to 6890 Wh I-Al(-1) at 100 mA cm(-2), as well as high stability during a mechanical recharging process

AN5D: Automated Stencil Framework for High-Degree Temporal Blocking on GPUs

Stencil computation is one of the most widely-used compute patterns in high performance computing applications. Spatial and temporal blocking have been proposed to overcome the memory-bound nature of this type of computation by moving memory pressure from external memory to on-chip memory on GPUs. However, correctly implementing those optimizations while considering the complexity of the architecture and memory hierarchy of GPUs to achieve high performance is difficult. We propose AN5D, an automated stencil framework which is capable of automatically transforming and optimizing stencil patterns in a given C source code, and generating corresponding CUDA code. Parameter tuning in our framework is guided by our performance model. Our novel optimization strategy reduces shared memory and register pressure in comparison to existing implementations, allowing performance scaling up to a temporal blocking degree of 10. We achieve the highest performance reported so far for all evaluated stencil benchmarks on the state-of-the-art Tesla V100 GPU

Abstracts from the 8th International Conference on cGMP Generators, Effectors and Therapeutic Implications

This work was supported by a restricted research grant of Bayer AG

Thermal Enhancement of Product Conductivity Permits Deep Discharge in Solid State Li-O2 Batteries

Li-O2 batteries are mainly limited by the poor conductivity of their discharge products as well as parasitic reactions with carbon-containing electrodes and electrolytes. Here, Li-O2 cells utilizing inorganic solid state electrolytes are investigated as a means to operate at elevated temperature, thereby increasing the conductivity of discharge products. Growth of dense, conductive LixOy products further removes the need for high surface area support structures commonly made of carbon. Patterned Au electrodes, evaporated onto Li7La3Zr2O12 (LLZO) solid electrolyte, are used to create a triple phase boundary for the nucleation of discharge product, with growth outward into the cell headspace with gaseous O2. Through capacity measurements and imaging, discharge product growths are estimated to reach a critical dimension of approximately 10 microns, far exceeding what would be possible for a conformal film based on its room temperature electronic conductivity. Raman spectroscopy and electrochemical mass spectrometry (EC-MS) are used to characterize the discharge chemistry and reveal a mixed lithium oxide character, with evidence of trace lithium hydroxides and initial carbonate contamination. These results showcase that thermal enhancement of Li-O2 batteries could be a viable strategy to increase capacity when paired with solid electrolytes

Thermal Enhancement of Product Conductivity Raises Capacity in Solid-State Li‑O₂ Batteries

Li-O2 batteries are mainly limited by the poor conductivity of their discharge products as well as parasitic reactions with carbon-containing electrodes and electrolytes. Here, Li-O2 cells utilizing inorganic solid-state electrolytes are investigated as a means to operate at elevated temperature, thereby increasing the conductivity of discharge products. Growth of dense, conductive LixOy products further removes the need for high-surface area support structures commonly made of carbon. Patterned Au electrodes, evaporated onto Li7La3Zr2O12 (LLZO) solid electrolyte, are used to create a triple-phase boundary for the nucleation of the discharge product, with growth outward into the cell headspace with gaseous O2. Through capacity measurements and imaging, discharge product growths are estimated to reach a critical dimension of approximately 10 μm, far exceeding what would be possible for a conformal film based on its room temperature electronic conductivity. Raman spectroscopy and electrochemical mass spectrometry are used to characterize the discharge chemistry and reveal a mixed lithium oxide character, with evidence of trace lithium hydroxides and initial carbonate contamination. These results showcase that thermal enhancement of Li-O2 batteries could be a viable strategy to increase capacity when paired with solid electrolytes

Linking CO₂ Sorption Performance to Polymer Morphology in Aminopolymer/Silica Composites through Neutron Scattering

Composites of poly­(ethylenimine) (PEI) and mesoporous silica are effective, reversible adsorbents for CO₂, both from flue gas and in direct air-capture applications. The morphology of the PEI within the silica can strongly impact the overall carbon capture efficiency and rate of saturation. Here, we directly probe the spatial distribution of the supported polymer through small-angle neutron scattering (SANS). Combined with textural characterization from physisorption analysis, the data indicate that PEI first forms a thin conformal coating on the pore walls, but all additional polymer aggregates into plug(s) that grow along the pore axis. This model is consistent with observed trends in amine-efficiency (CO₂/N binding ratio) and pore size distributions, and points to a trade-off between achieving high chemical accessibility of the amine binding sites, which are inaccessible when they strongly interact with the silica, and high accessibility for mass transport, which can be hampered by diffusion through PEI plugs. We illustrate this design principle by demonstrating higher CO₂ capacity and uptake rate for PEI supported in a hydrophobically modified silica, which exhibits repulsive interactions with the PEI, freeing up binding sites