Small Methods最新文献

X-ray scattering is a highly versatile characterization method and has seen widespread use across all fields of science. Previous review articles pertaining to small- and wide-angle X-ray scattering (SWAXS) have either been highly specific or narrow in scope. Generally, other SWAXS reviews have been mainly tailored toward characterizing biological protein samples or polymers. However, there appears to be a literature gap in how SWAXS may be used in characterizing self-assembled systems, more specifically, liquid crystals. SWAXS is a crucial technique used for characterizing liquid crystals, offering valuable crystallographic insights that cannot be directly observed by optical or spectroscopic methods. Unlike spectroscopic techniques, SWAXS can provide valuable nanoscale structural information over a larger volume of material, and it will be discussed in detail herein. This review seeks to fill that gap as well as aid in educating and welcoming prospective scientists interested in learning to use the technique for materials characterization. Several studies will be covered on how SWAXS was used to characterize the most common self-assembled phases.

Selectively dispersed Ru nanoparticles (NP ∼3 nm) on WS₂ nanosheets (NS) (WS₂@Ru) are synthesized by a two-step strategy-plasma exfoliation of bulk WS₂ into nanosheets and subsequent in situ polyol reduction. The dispersion of Ru NP near WS₂ NS edges is confirmed with transmission electron microscopy and predicted with a much larger binding energy for Ru NP on edges than on basal planes (-11.01 vs. -8.41 eV) with density function theory (DFT) calculation. X-ray absorption near-edge spectroscopy reveals electron transfer from Ru to W. WS₂@Ru3 (6 wt.% Ru NP) sample shows optimal hydrogen evolution reaction (HER) activity with an overpotential of 83 mV at 10 mA cm^{- 2} and a Tafel slope of 56 mV dec^-1, significantly smaller than those of pristine WS₂ NS (283 mV and 146 mV dec^-1), and WS₂@Ru3 retains excellent stability after 1000 cycles. DFT calculations also show lower Gibbs free energies of hydrogen adsorption (-0.21 eV) at WS₂@Ru3 edge sites, indicating favorable HER. These enhancements are attributed to the synergistic interaction between Ru NP and WS₂ nanosheets that modulates the electronic structure at the active sites. Our approach of creating a selectively-dispersed 0D/2D heterostructure offers a sustainable and scalable strategy for fabricating superior electrocatalysts for hydrogen production.

Aqueous zinc-iodine (Zn─I₂) batteries demonstrate immense potential for energy storage owing to their inherent safety, stable voltage plateau, and environmental friendliness. However, the slow iodine conversion, polyiodide shuttle effect, and uncontrollable Zn dendrites impede the improvement of their performance. Herein, we successfully designed a bifunctional core-shell host derived from BiHCF@ZIF-8, which consists of a porous carbon matrix encapsulating abundant metal catalytic sites and trace N-doping (BZPC). This superior multi-site co-doped hierarchical porous structure can serve as a high-efficiency iodine carrier to effectively confine iodine species and enhance their conversion kinetics. Simultaneously, the BZPC can also be applied as a functional modification layer to induce uniform Zn deposition, thereby achieving a dendrite-free Zn anode. The assembled Zn//BZPC@I₂ batteries and BZPC@Zn symmetric cells can operate stably at ultrahigh current densities of 50 C and 100 mA cm^-2, respectively. Through a synergistic optimization strategy of "one host for dual purposes", the BZPC@Zn//BZPC@I₂ batteries achieve an ultralong lifespan of 28 000 stable cycles even at an ultrahigh current density of 50 C. This study not only pioneers the difunctional BZPC for both iodine host design and zinc interface engineering but also establishes an innovative and scalable strategy for developing long-life and high-rate Zn─I₂ batteries.

Combining functional magnetic resonance imaging (fMRI) with real‑time monitoring of neurochemicals, such as ions, offers powerful opportunities for multimodal investigation of brain function through simultaneous acquisition of local neurochemical dynamics and whole-brain neural activation patterns. However, current combination approaches predominantly rely on fluorescent calcium imaging, which cannot effectively capture diverse extracellular ion dynamics in deep brain regions, thereby constraining comprehensive studies of various neurological disorders and physiological state transitions. Here, implantable MRI-compatible fiber ion sensors (MISs) are developed to realize concurrent extracellular ion monitoring and fMRI. The MIS employs a simplified architecture with an ion-selective membrane conformally coated on a conductive polymer fiber that simultaneously serves as both an ion-to-electron transduction interface and an electrical conductor. This design enables stable, high-sensitivity monitoring of calcium and potassium ions while maintaining negligible imaging artifacts during 7 T MRI. As a proof of concept, concurrent monitoring of extracellular ion fluctuations via the implanted MIS and whole-brain fMRI is realized during anesthesia transitions in rats, establishing the MIS as an effective tool for multimodal exploration of neural activity.

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In article number 2500827, Jo and co-workers highlight the critical role of electrolyte composition in modulating the reactivity of crystal water at the Prussian blue (PB) cathode–electrolyte interface in sodium-ion batteries (SIBs). NaTFSI mitigates interfacial degradation by disrupting hydrogen-bond networks and suppressing water-mediated side reactions, whereas NaClO₄ intensifies water coordination, inducing cathode-electrolyte interphase instability. These findings provide valuable guidance for optimizing electrolytes in PB-based SIBs.

The instability of the electrode-electrolyte interface and sluggish kinetics in zinc metal batteries (ZMBs) accelerate their degradation. Modifying the interfacial layer and Zn²⁺ solvation structure presents promise for enhancing ZMBs' longevity. Herein, a high-entropy electrolyte is developed by incorporating multiple ether-based solvents, a fluorine-rich ether diluent, and H₂O as a co-solvent with Zn(BF₄)₂ salt. The diverse solvents enrich the coordination species in the Zn²⁺ solvation sheath, increasing the solvation entropy and minimizing solvent clustering. This enhanced solvation entropy weakens Zn²⁺-solvent interactions and facilitates the desolvation process, significantly accelerating interfacial reaction kinetics while maintaining low polarization. Additionally, the dissociated solvents and anions migrate to the electrode, yielding a robust and micron-thick ZnF₂ interfacial layer that suppresses zinc dendrite and byproducts. Notably, without compromising the anti-corrosion and anti-freezing properties, H₂O regulates the interfacial layer composition and structure through hydrolysis, ensuring a dense and uniform ZnF₂ layer. Consequently, within this high-entropy electrolyte, Zn/Zn symmetric cells provide stable cycling for over 2000 h (1 mA cm^-2 and 1 mAh cm^-2) without polarization. The high Coulombic efficiency of 99.55% in Zn/Cu asymmetric cells demonstrates the excellent reversibility of zinc plating/stripping. Moreover, Zn/polyaniline full cells achieve a lifespan exceeding 1000 cycles with promising capacity retention.

All-solid-state sodium-ion batteries (ASSSIBs) based on halide solid electrolytes (HSEs) are emerging as promising systems for high energy density and stable energy storage. Although HSEs are generally regarded as compatible with high-voltage oxide cathodes, their interfacial stability remains insufficiently understood. Here, we evaluate the interfacial chemical compatibility between representative HSEs and high-voltage sodium cathode materials through mutual decomposition reaction energy calculations. The analysis reveals interfacial instability of HSEs against high voltage cathodes, challenging the prevailing assumption of their intrinsic stability and highlighting the need for targeted interface design. To address this issue, a high-throughput computational screening of 12 800 sodium-containing compounds was performed, identifying several coating materials that effectively suppress interfacial reaction driving forces. These coatings promote stable SE-cathode interfaces, ensuring chemical compatibility under high voltage operation. This study establishes a strategic framework for interfacial design that deepens the understanding of HSE stability and advances the development of durable, high-energy ASSSIBs.

Trinuclear copper complexes that emulate the active sites of multicopper oxidases (MCOs) are of broad biological interest. Here, a monoatomic-node strategy combined with solvent reduction was used to construct a rare trinuclear copper MOF featuring a planar, equilateral-triangular Cu^I _0.6Cu^II _2.4 core. The Cu^I _0.6Cu^II _2.4-MOF nanozyme shows enzymatic activity 37.2 times than that of laccase and 13.6 times than that of a Cu^II ₃-MOF analogue, retains high chemical stability from pH 4 to 12, and lowers production cost by 16.2-fold relative to natural laccase. DFT calculations attribute the superior performance to the introduction of Cu⁺, which yields a more favorable electronic structure, reaction energy landscape, and intermediate binding than in Cu^II ₃-MOF. Consequently, Cu^I _0.6Cu^II _2.4-MOF efficiently degrades phenolic pollutants and enables colorimetric discrimination and detection of 11 phenols as a colorimetric sensor array. It also affords sensitive detection of epinephrine and dopamine, with limits of detection of 6.5 and 10 µm, respectively. Overall, this work demonstrates a laccase-inspired route to high-activity, low-cost MOFs with strong potential for environmental remediation and biosensing.

Aqueous rechargeable zinc metal batteries (ARZMBs) have attracted increasing attention as sustainable energy storage systems capable of mitigating the intermittency of renewable energy, due to their high safety, low cost, and environmental friendliness. However, their practical applications are still hindered by several critical issues, including poor low-temperature performance, slow ion diffusion of the electrolytes, and severe gas generation reaction at the interface between the electrolyte and the electrode. In recent years, the design concept of high-entropy electrolytes (HEEs) has been introduced into aqueous energy storage systems. By introducing diverse ions or solvent molecules, it is possible to enhance the entropies of the system, including configurational, tetrahedral, and mixing entropy, thereby enabling control over the solvation structure, hydrogen bond network, and interfacial reactions. However, the concept of entropy remains relatively abstract and challenging for newcomers to grasp. Moreover, the performance enhancements achievable through different types of entropy vary considerably, and a systematic review comparing these effects is currently lacking. This work reviews the fundamental principles of HEEs, strategies for entropy modulation, and recent advances in their applications for ARZMBs. Special emphasis is placed on the mechanisms by which configurational entropy optimizes the Zn²⁺ solvation structure, as well as the role of tetrahedral entropy in modulating the hydrogen bond network. Finally, we discuss the challenges and future directions for HEEs in the development of high-performance, wide-temperature-range, and long-lifespan ARZMBs, with the aim of providing theoretical guidance to advance green energy storage technologies.

The stringent safety protocols required for hydrofluoric acid (HF) based MAX phase etching and the reliance on material characterization tools such as XRD, SEM, EDS and XPS to study etching make the MXene research challenging. Here, we have employed ²⁷Al NMR spectroscopy for the rapid detection of selective etching, directly from the etching supernatant, of soluble aluminum species generated during the MAX phase etching reaction. This technique was applied to the development of a new etching protocol for Ti₃AlC₂ MAX phase using the less hazardous hexafluorosilicic acid. The etching process was studied using a combination of ²⁷Al and ¹⁹F NMR spectroscopies where it was demonstrated to be free of HF or free fluoride in quantities detectable by ¹⁹F NMR, and that the primary etching byproduct is H₃AlF₆. ¹⁹F NMR spectroscopy was additionally proven to be a viable technique to quantify the extent of etching using trifluoroacetic acid as an internal standard.