Search

Theperformance of battery electrode materials is strongly affectedby inefficiencies in utilization kinetics and cycle life as well assize effects. Observations of phase transformations in these materialswith high chemical and spatial resolution can elucidate the relationshipbetween chemical processes and mechanical degradation. Soft X-rayptychographic microscopy combined with X-ray absorption spectroscopyand electron microscopy creates a powerful suite of tools that weuse to assess the chemical and morphological changes in lithium ironphosphate (LiFePO4) micro- and nanocrystals that occurupon delithiation. All sizes of partly delithiated crystals were foundto contain two phases with a complex correlation between crystallographicorientation and phase distribution. However, the lattice mismatchbetween LiFePO4and FePO4led to severe fracturingon microcrystals, whereas no mechanical damage was observed in nanoplates,indicating that mechanics are a principal driver in the outstandingelectrode performance of LiFePO4nanoparticles. These resultsdemonstrate the importance of engineering the active electrode materialin next generation electrical energy storage systems, which will achievetheoretical limits of energy density and extended stability. Thiswork establishes soft X-ray ptychographic chemical imaging as an essentialtool to build comprehensive relationships between mechanics and chemistrythat guide this engineering design. [ABSTRACT FROM AUTHOR]

[Display omitted] • STXM analysis shows OSC changes in CeO 2 from additives (Cu and Mg). • XANES analysis of chemical maps (from STXM image) provides the Ce3+ ratio. • Proper amount of Mg addition to CeO 2 increases OSC. • CCM75 catalyst exhibits the highest catalytic activity, attributed to its superior OSC. Here, scanning transmission X-ray microscopy (STXM) analysis was utilized to directly present visual evidence of changes in oxygen storage capacity (OSC) when small amounts of an additive were incorporated into CeO 2. Specifically, the chemical map measured by STXM analysis differentiated between Cu-rich and Ce-rich areas to derive the proportion of Ce3+. Additionally, we found that the dispersion of Cu significantly influenced the formation of OSC. The findings were applied to the high-temperature water–gas shift reaction for producing high-purity hydrogen from waste-derived syngas, establishing a correlation with catalyst performance. Consequently, the CCM75 (Ce/Mg = 75/25) catalyst demonstrated the highest Cu dispersion and OSC values (6.9 %, 800.3 μmol O /g cat), and it also showed the highest CO conversion (79 % at 450 °C) and stability (−7.7 % at 450 °C after 50 h), attributed to the significant presence of active Cu. This study confirms previously reported interactions between Cu and CeO 2 and uncovers the significant roles of Cu and Mg in this catalysis system, providing new understanding of the mechanisms that facilitate OSC improvement. [ABSTRACT FROM AUTHOR]

Objective: This trial was conducted to explore the impact of different wilting time of Italian ryegrass (IRG) in the field on the nutritional quality and fermentation characteristics of its silage., Methods: The harvested IRG was directly wilted in the field for 0 day (W0), 1 day (W1), 2 days (W2), and 3 days (W3), respectively, and tedded every 6 hours. And the preserved IRG was sampled at 1, 2, 3, 5, 10, 20, 30, and 45 days after ensiling and three replicates per treatment., Results: With the extension of wilting, the dry matter (DM) content and pH value of wilted IRG gradually increased (p<0.05). There was a downward trend in; neutral detergent fiber (NDF), acid detergent fiber (ADF), and hemicellulose with the increase of wilting time, but only W2 and W3 were significantly different from W0 (p<0.05). Crude protein (CP), in vitro DM digestibility), total digestible nutrients (TDN), and relative feed value decreased significantly with the increase of wilting time (p<0.05), except for W1. After 45 days of ensiling, W1 had the highest CP, TDN, and the lowest ADF and NDF. During ensiling, the increase of acetic acid and the decrease of WSC in W0 and W1 were similar, but the accumulation rate of lactic acid in W0 was faster than that in W1, resulting in the lowest pH value in W0. After 5 days of ensiling, the ratio of lactic acid to acetic acid in W1 stabilized at around 3:1, while W0 kept changing., Conclusion: Italian ryegrass that wilted in the field for 1 day effectively improved the dynamic changes in CP, TDN, ADF, and NDF and fermentation quality of silage. Therefore, in practice, W1 was more recommended in production of IRG silage.

Objective: In this study, we explored the effect of fruit and vegetable waste addition on the quality of corn stalk silage., Methods: Corn stalks were ensiled 20 days after ear harvesting and mixed with fruit and vegetable waste (FVW) consisting of apple, orange, broccoli, and Chinese cabbage waste as 3% of fresh matter. Fruit waste consisted of solid residue obtained after juicing, and vegetable waste was collected from farms and cut into small pieces (2 to 3 cm). The materials were stored anaerobically in 20-L silo buckets and opened after 60 days of fermentation., Results: There were significant differences in dry matter (DM), acid detergent fiber (ADF), neutral detergent fiber (NDF), total digestible nutrient (TDN), and relative feed value (RFV) levels in FVW derived from all tested raw materials (p<0.05). Corn stalk mixed with orange waste (CSOW) had the highest DM content (28.77%), lowest ADF and NDF content (47.78% and 26.62% of DM, respectively), and highest TDN and RFV content (69.21 and 133, respectively). After 60 days, there were significant differences in all chemical parameters examined (p<0.05). Corn stalk mixed with broccoli waste (CSBW) had the lowest DM loss (2.23%), and the CSOW group had the lowest NDF and ADF content and highest in vitro DM digestibility. CSBW had the lowest pH and ammonia nitrogen content, but the highest lactic acid/acetic acid ratio among the treatment groups. CSOW had the highest lactic acid content (2.27% of DM). The microbial contents of each group differed only in lactic acid bacteria counts before and after ensiling, showing a slight increase (p>0.05) and significant decreases in yeast and mold counts (p<0.05) after ensiling., Conclusion: These findings confirmed that mixing various FVW materials, particularly orange waste, with corn stalks improved the nutritional value of silage. Adding broccoli waste resulted in better fermentation quality than the addition of other FVW materials.

Objective: A study was conducted to quantify the performance differences of the nearinfrared spectroscopy (NIRS) calibration models developed with different degrees of hay sample preparations., Methods: A total of 227 imported alfalfa (Medicago sativa L.) and another 360 imported timothy (Phleum pratense L.) hay samples were used to develop calibration models for nutrient value parameters such as moisture, neutral detergent fiber, acid detergent fiber, crude protein, and in vitro dry matter digestibility. Spectral data of hay samples prepared by milling into 1-mm particle size or unground were separately regressed against the wet chemistry results of the abovementioned parameters., Results: The performance of the developed NIRS calibration models was evaluated based on R2, standard error, and ratio percentage deviation (RPD). The models developed with ground hay were more robust and accurate than those with unground hay based on calibration model performance indexes such as R2 (coefficient of determination), standard error, and RPD. Although the R2 of calibration models was mainly greater than 0.90 across the feed value indexes, the R2 of cross-validations was much lower. The R2 of cross-validation varies depending on feed value indexes, which ranged from 0.61 to 0.81 in alfalfa, and from 0.62 to 0.95 in timothy. Estimation of feed values in imported hay can be achievable by the calibrated NIRS. However, the NIRS calibration models must be improved by including a broader range of imported hay samples in the modeling., Conclusion: Although the analysis accuracy of NIRS was substantially higher when calibration models were developed with ground samples, less sample preparation will be more advantageous for achieving rapid delivery of hay sample analysis results. Therefore, further research warrants investigating the level of sample preparations compromising analysis accuracy by NIRS.

We propose an interface-engineered oxide-supported Pt nanoparticle-based catalyst with improved low-temperature activity toward CO oxidation. By wet-impregnating 1 wt % Ce on TiO 2 , we synthesized hybrid oxide support of CeO x -TiO 2 , in which dense CeO x clusters formed on the surface of TiO 2 . Then, the Pt/CeO x -TiO 2 catalyst was synthesized by impregnating 2 wt % Pt on the CeO x -TiO 2 supporting oxide. Pt-CeO x -TiO 2 triphase interfaces were eventually formed upon impregnation of Pt on CeO x -TiO 2 . The Pt-CeO x -TiO 2 interfaces open up the interface-mediated Mars-van Krevelen CO oxidation pathway, thus providing additional interfacial reaction sites for CO oxidation. Consequently, the specific reaction rate of Pt/CeO x -TiO 2 for CO oxidation was increased by 3.2 times compared with that of Pt/TiO 2 at 140 °C. Our results demonstrate a widely applicable and straightforward method of catalytic activation of the interfaces between metal nanoparticles and supporting oxides, which enabled fine-tuning of the catalytic performance of oxide-supported metal nanoparticle classes of heterogeneous catalysts.

Redox-driven phase transformations in solids determine the performance of lithium-ion batteries, crucial in the technological transition from fossil fuels. Couplings between chemistry and strain define reversibility and fatigue of an electrode. The accurate definition of all phases in the transformation, their energetics, and nanoscale location within a particle produces fundamental understanding of these couplings needed to design materials with ultimate performance. Here we demonstrate that scanning X-ray diffraction microscopy (SXDM) extends our ability to image battery processes in single particles. In LiFePO 4 crystals equilibrated after delithiation, SXDM revealed the existence of domains of miscibility between LiFePO 4 and Li 0.6 FePO 4 . These solid solutions are conventionally thought to be metastable, and were previously undetected by spectromicroscopy. The observation provides experimental verification of predictions that the LiFePO 4 -FePO 4 phase diagram can be altered by coherency strain under certain interfacial orientations. It enriches our understanding of the interaction between diffusion, chemistry, and mechanics in solid state transformations.

Electrochemical oxidation of carbonate esters at the Li(x)Ni(0.5)Mn(1.5)O(4-δ)/electrolyte interface results in Ni/Mn dissolution and surface film formation, which negatively affect the electrochemical performance of Li-ion batteries. Ex situ X-ray absorption (XRF/XANES), Raman, and fluorescence spectroscopy, along with imaging of Li(x)Ni(0.5)Mn(1.5)O(4-δ) positive and graphite negative electrodes from tested Li-ion batteries, reveal the formation of a variety of Mn(II/III) and Ni(II) complexes with β-diketonate ligands. These metal complexes, which are generated upon anodic oxidation of ethyl and diethyl carbonates at Li(x)Ni(0.5)Mn(1.5)O(4-δ), form a surface film that partially dissolves in the electrolyte. The dissolved Mn(III) complexes are reduced to their Mn(II) analogues, which are incorporated into the solid electrolyte interphase surface layer at the graphite negative electrode. This work elucidates possible reaction pathways and evaluates their implications for Li(+) transport kinetics in Li-ion batteries.