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The sol-gel method is efficient and cost-effective for synthesizing SnO2 sol, wherein SnO2 nanocrystallites (NCs) are stabilized by electric double-layer of solvated ions tightly bound to their surface. However, this strong binding makes the removal of electric double-layer residues from the SnO2 electron transport layer (ETL) to be difficult at low temperatures. This hinders both the close contact and subsequent growth among adjacent SnO2 NCs, leading to severe carriers scattering at grain boundary, adversely affecting the electrical properties of SnO2 ETL. Herein, SnO2 sol is synthesized via an ethanol-based sol-gel method and aqueous ammonia (NH3H2O) is introduced to effectively clean stubborn electric double-layer residues within the SnO2 ETL at a low temperature (80 degrees C). Removing residues reduces the gap among adjacent SnO2 NCs and promotes further reconstructed growth through oriented attachment (OA), thereby reducing the number of grain boundaries. Hence, the energy barriers for electron transport decrease within the SnO2 ETL. Furthermore, MHP prepared on the treated ETL has fine-tuned energy level alignment, improving the electron extraction capacity. Consequently, flexible perovskite solar cells (f-PSCs) incorporating this ETL achieved a notable increase in power conversion efficiency, rising from 19.16% to 23.71%, as well as superior mechanical stability.

Cobalt-free lithium nickel oxide (LNO) has garnered significant interest as the end member of high-nickel layered oxide cathodes for next-generation batteries. However, its practical performance notably underperforms expectations because of the structural degradation and unstable interfacial chemistry with electrolytes during cycling. Here, we report that a durable cathode-electrolyte interface (CEI), enriched by in situ formed sulfides and borides, can inhibit LNO structural degradation and suppress Ni ion dissolution. With the CEI protection, the stability of LNO can be remarkably extended, and batteries demonstrate a capacity retention rate of 84% (30 °C) and 79% (50 °C) after 200 cycles at 1C, respectively. These results demonstrate that enriching CEI with sulfur-containing species can effectively stabilize the interfacial chemistry of LNO, particularly at an elevated temperature of 50 °C. This finding provides valuable perspectives on designing electrolytes for cobalt-free LNO and other high-Ni cathodes toward the development of next-generation high-energy-density lithium-ion batteries. © 2024 American Chemical Society.

Cu-based catalysts have been identified as the most promising candidates for generation of C2+ products in electrochemical CO2 reduction reaction. Defect engineering in catalysts is a widely employed strategy for promoting C−C coupling on Cu. However, comprehensive understanding of defect structure-to-activity relationship has not been obtained. In this study, controllable defects generation is achieved, which leads to a series of Cu-based catalysts with various phase mixing degrees. It is observed that the Faradaic efficiency toward C2+ products increases with the phase mixing degree, reaching 81 % at maximum. In situ infrared absorption spectroscopy reveals that the catalysts with higher phase mixing degree tend to form *CO more easily and possess higher retention of *CO under high overpotential window, thereby promoting C−C coupling. This work sheds new light on the relationship between defects and C−C coupling, and the rational developed of more advanced Cu-base catalysts.

Structural and physiochemical properties contribute to the biological adaptation of deep-sea animals to their harsh living environment but have hardly been investigated systematically. In the present study, we for the first time applied various material characterization techniques including transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and Fourier-transform infrared (FT-IR) spectroscopy to investigate the shell microstructures and chemical composition of a deep-sea limpet Eulepetopsis crystallina collected from the Tiancheng hydrothermal vent field at a depth of around 2,700 m in the Southwest Indian Ocean. Analyses of shell microstructural morphology and diffraction patterns of E. crystallina explicitly revealed the layered structures, exfoliation characteristics, and crystallographic orientation of each layer’s unit cell which was tilted at a small angle sequentially. In comparison with ordinary shallow-water limpet Cellana toreuma shells, E. crystallina shells showed a unique chemical composition and contained pure calcite of calcium carbonate polymorph and the trace of phosphate originated from regional phosphatic sediments of the Southwest Indian Ocean. The further microscopic analyses indicated that the shell of the deep-sea limpet E. crystallina features integrated and untruncated layer structures with a compressed width, possibly owning to the ultra-high hydrostatic pressure, which confirmed the effects of the living environment on the shell microstructure of deep-sea animals.

This study reveals atomic-scale observations of the high temperature stability of platinum nanoparticles deposited on pristine graphene oxide (PtNPs/GO) and platinum nanoparticles deposited on water-etched graphene oxide (PtNPs/GO-H2O) as two representative catalyst systems for dehydrogenation. With the aid of in-situ transmission electron microscopy (TEM), these two kinds of catalysts can be examined at actual working temperatures up to 800 °C, and notably, PtNPs/GO-H2O exhibits the higher temperature stability even at 700 °C. The statistical data of in-situ time-lapsed TEM images demonstrate the size variations of the sintering Pt nanoparticles which are in accordance with the Ostwald ripening process. We further discover the tendency towards the preferential exposure of high-index Pt nanocrystal facets (higher surface energy sides) for the PtNPs/GO under thermal treatment from 25 °C to 400 °C, which leads to accelerate the nanoparticle aggregations, providing microscopic evidence of the catalyst instability at high temperatures. © 2020 Elsevier Inc.

Twisted bilayer graphene provides a new two-dimensional platform for studying electron interaction phenomena and flat band properties such as correlated insulator transition, superconductivity and ferromagnetism at certain magic angles. Here, we present experimental characterization of interaction effects and superconductivity signatures in p-type twisted double-bilayer WSe2. Enhanced interlayer interactions are observed when the twist angle decreases to a few degrees as reflected by the high-order satellites in the electron diffraction patterns taken from the reconstructed domains from a conventional moiré superlattice. In contrast to twisted bilayer graphene, there is no specific magic angle for twisted WSe2. Flat band properties are observable at twist angles ranging from 1 to 4 degrees. Our work has facilitated future study in the area of flat band related properties in twisted transition metal dichalcogenide layered structures.

Twisted bilayer graphene provides a new two-dimensional platform for studying electron interaction phenomena and flat band properties such as correlated insulator transition, superconductivity and ferromagnetism at certain magic angles. Here, we present experimental characterization of interaction effects and superconductivity signatures in p-type twisted double-bilayer WSe2. Enhanced interlayer interactions are observed when the twist angle decreases to a few degrees as reflected by the high-order satellites in the electron diffraction patterns taken from the reconstructed domains from a conventional moiré superlattice. In contrast to twisted bilayer graphene, there is no specific magic angle for twisted WSe2. Flat band properties are observable at twist angles ranging from 1 to 4 degrees. Our work has facilitated future study in the area of flat band related properties in twisted transition metal dichalcogenide layered structures.