Capillary imbibition in variably saturated porous media is important in defining displacement processes and transport in the vadose zone and in low‐permeability barriers and reservoirs. Nonintrusive imaging in real time offers the potential to examine critical impacts of heterogeneity and surface properties on imbibition dynamics. Neutron radiography is applied as a powerful imaging tool to observe temporal changes in the spatial distribution of water in porous materials. We analyze water imbibition in both homogeneous and heterogeneous low‐permeability sandstones. Dynamic observations of the advance of the imbibition front with time are compared with characterizations of microstructure (via high‐resolution X‐ray computed tomography (CT)), pore size distribution (Mercury Intrusion Porosimetry), and permeability of the contrasting samples. We use an automated method to detect the progress of wetting front with time and link this to square‐root‐of‐time progress. These data are used to estimate the effect of microstructure on water sorptivity from a modified Lucas‐Washburn equation. Moreover, a model is established to calculate the maximum capillary diameter by modifying the Hagen‐Poiseuille and Young‐Laplace equations based on fractal theory. Comparing the calculated maximum capillary diameter with the maximum pore diameter (from high‐resolution CT) shows congruence between the two independent methods for the homogeneous silty sandstone but less effectively for the heterogeneous sandstone. Finally, we use these data to link observed response with the physical characteristics of the contrasting media—homogeneous versus heterogeneous—and to demonstrate the sensitivity of sorptivity expressly to tortuosity rather than porosity in low‐permeability sandstones.

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Ni-rich layered oxides are very promising high energy density cathodes for lithium-ion batteries. A small amount of Ni, Co, and Mn is substituted by Al to study the structural evolution, electrochemical behaviors, and properties of Ni-rich cathodes. Neutron diffraction results demonstrate that Al substitution for Ni, Co, and Mn results in remarkable differences in materials structure and reduced the cation mixing with different degrees. The distinct differences in electrochemistry including rate capability, long-term cycling stability, average operating voltage, and polarization effect are systemically discussed, which can be ascribed to the material structural evolution. In contrast, LiNi 0.6 Co 0.2 Mn 0.15 Al 0.05 O 2 can deliver a very high specific capacity of 120 mAh g −1 at 10C and an 82.4% cycling stability after prolonged 500 cycles at 2C. This study offers a fundamental insight into optimizing the materials structure and composition of layered oxide cathodes with higher Ni content for lithium-ion batteries.

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A palladium-catalyzed cross-coupling of unactivated alkylzinc reagents with 2-bromo-3,3,3-trifluoropropene (BTP) has been developed, which was used as a key step to prepare a series of trifluoromethylated and difluoromethylated amino acids.

Exploiting high-performance cathodes is still in need for sodium-ion batteries, which is critical to promote their commercialization. Layered sodium manganese oxide cathodes show low cost and natural abundance but suffer from poor cycling life and rate capacity. Herein, electrochemically inert Ti4+ and active Ni2+ are used to replace some Mn ions in Na0.62MnO2, and neutron power diffraction results demonstrate a negligible change in the sizes of the metal layer and Na-ion layer in the structure. Although Na0.62[Ni0.12Ti0.12Mn0.76]­O2 and Na0.62MnO2 share the same Na content in pristine materials and theoretical capacity, the improved performance of Na0.62[Ni0.12Ti0.12Mn0.76]­O2 stems from the suppressed phase transitions and ordering process, alleviated Jahn–Teller distortion, and a high Na utilization of 73.8% compared with 62.2% for Na0.62MnO2. Ti4+ stabilizes the crystal structure and hinders the multiple phase transitions and Na+/vacancy ordering upon cycling, and Ni2+ improves the working voltage and compensates the capacity loss associated with decreased Mn3+ content. Na0.62[Ni0.12Ti0.12Mn0.76]­O2 exhibits an average working voltage of about 3.5 V, a great rate capability, and cycling stability of 76.8% capacity retention after 120 cycles in the voltage range of 2.5–4.5 V. The work offers an insight into enhancing advanced layered sodium manganese oxide cathode materials for sodium-ion batteries.

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