Nano Research最新文献

Topochemical transformation has emerged as a promising method for fabricating two-dimensional (2D) materials with precise control over their composition and morphology. However, the large-scale synthesis of ultrathin 2D materials with controllable thickness remains a tremendous challenge. Herein, we adopt an efficient topochemical synthesis strategy, employing a confined reaction space to fabricate ultrathin 2D Sn₄P₃ nanosheets in large-scale. By carefully adjusting the rolling number during the processing of Sn/Al foils, we have successfully fabricated Sn₄P₃ nanosheets with varied layer thicknesses, achieving a remarkable minimum thickness of two layers (~ 2.2 nm). Remarkably, the bilayer Sn₄P₃ nanosheets display an exceptional initial capacity of 1088 mAh·g⁻¹, nearing the theoretical value of 1230 mAh·g⁻¹. Furthermore, we reveal their high-rate property as well as outstanding cyclic stability, maintaining capacity without fading more than 3000 cycles. By precisely controlling the layer thickness and ensuring nanoscale uniformity, we enhance the lithium cycling performance of Sn₄P₃, marking a significant advancement in developing high-performance energy storage systems.

Anomalous thermal expansion, or other words, negative thermal expansion (NTE), resulting from the lattice contraction upon temperature increasing, has been an enduring topic for material science and engineering. The variation of a lattice go with the temperature is straightly originated from its electronic structures and is inseparable from those physical properties. In the past several decades, many efforts have been made to searching new series of NTE compounds or control the thermal expansion performance in order to supply various demands of different extreme applications. These development of new NTE systems also dependences on the theoretical studies. Here, we carried out theoretical calculation on CrB₂ and FeZr₂ with anisotropic negative thermal expansion. Intriguingly, theoretical calculations reveal that the binding of either Cr-Cr pair or Fe-Fe pair is relatively small. The results reveal that the origin of NTE is the ordered magnetic state during the increasing of temperature. The localized electrons would prevent the lattice parameters increase with heating, which shows macroscopic NTE phenomenon.

Interaction between heterogeneous, nanometer-sized building blocks (NSBBs) is fascinating from viewpoints of both structures and functions. We report the co-assembly of fullerene C₆₀ and a chiral silver nanocluster (Ag₆), which yields C₆₀ nanoarchitecture decorated with a small amount of Ag₆. While Ag₆ exhibits circular dichroism (CD) signal mainly in the ultraviolet (UV) region, the signal of the C₆₀-Ag₆ hybrid extends to visible region (over 700 nm). Up to five pairs of CD signals were distinguished, which match well with the absorption of the C₆₀ crystal. The successful chirality transfer from the guest of Ag₆ to C₆₀-dominated supramolecular system indicates that the “sergeants and soldiers” effect is valid in architectonics of NSBBs. In addition, the doping of Ag₆ leads to pronounced nonlinear optical response, paving a new way for the development of chiral optical materials.

High-entropy alloys (HEAs) are promising candidates for the electrocatalyst of hydrogen evolution reaction (HER) due to their unique properties such as cocktail electronic effect and lattice distortion effect. Herein, the ultrasmall (sub-2 nm) nanoparticles of PtRuCoNiCu HEA with uniform element distribution are highly dispersed on hierarchical N-doped carbon nanocages (hNCNC) via low-temperature thermal reduction, denoted as us-HEA/hNCNC. The optimal us-HEA/hNCNC exhibits excellent HER performance in 0.5 M H₂SO₄ solution, achieving an ultralow overpotential of 19 mV at 10 mA·cm⁻² (without iR-compensation), high mass activity of 13.1 A·mg_{noble metals}⁻¹ at −0.10 V and superb stability with a slight overpotential increase of 3 mV after 20,000 cycles of cyclic voltammetry scans, much superior to the commercial Pt/C (20 wt.%). The combined experimental and theoretical studies reveal that the Pt&Ru serve as the main active sites for HER and the CoNiCu species modify the electron density of active sites to facilitate the H* adsorption and achieve an optimum M-H binding energy. The hierarchical pore structure and N-doping of hNCNC support also play a crucial role in the enhancement of HER activity and stability. This study demonstrates an effective strategy to greatly improve the HER performance of noble metals by developing the HEAs on the unique hNCNC support.

The advancement of lithium-based batteries has spurred anticipation for enhanced energy density, extended cycle life and reduced capacity degradation. However, these benefits are accompanied by potential risks, such as thermal runaway and explosions due to higher energy density. Currently, liquid organic electrolytes are the predominant choice for lithium batteries, despite their limitations in terms of mechanical strength and vulnerability to leakage. The development of polymer electrolytes, with their high Young’s modulus and enhanced safety features, offers a potential solution to the drawbacks of traditional liquid electrolytes. Despite these advantages, polymer electrolytes are still susceptible to burning and decomposition. To address this issue, researchers have conducted extensive studies to improve their flame-retardant properties from various perspectives. This review provides a concise overview of the thermal runaway mechanisms, flame-retardant mechanisms and electrochemical performance of polymer electrolytes. It also outlines the advancements in flame-retardant polymer electrolytes through the incorporation of various additives and the selection of inherently flame-retardant matrix. This review aims to offer a comprehensive understanding of flame-retardant polymer electrolytes and serve as a guide for future research in this field.