RESUMEN
Weak van der Waals interactions between interlayers of two-dimensional layered materials result in disabled across-interlayer electron transfer and poor layered structural stability, seriously deteriorating their performance in energy applications. Herein, we propose a novel covalent assembly strategy for MoS2 nanosheets to realize unique MoS2 /SnS hollow superassemblies (HSs) by using SnS nanodots as covalent linkages. The covalent assembly based on all-inorganic and carbon-free concept enables effective across-interlayer electron transfer, facilitated ion diffusion kinetics, and outstanding mechanical stability, which are evidenced by experimental characterization, DFT calculations, and mechanical simulations. Consequently, the MoS2 /SnS HSs exhibit superb rate performance and long cycling stability in lithium-ion batteries, representing the best comprehensive performance in carbon-free MoS2 -based anodes to date. Moreover, the MoS2 /SnS HSs also show excellent sodium storage performance in sodium-ion batteries.
RESUMEN
Incorporating nanoscale Si into a carbon matrix with high dispersity is desirable for the preparation of lithium-ion batteries (LIBs) but remains challenging. A space-confined catalytic strategy is proposed for direct superassembly of Si nanodots within a carbon (Si NDsâC) framework by copyrolysis of triphenyltin hydride (TPT) and diphenylsilane (DPS), where Sn atomic clusters created from TPT pyrolysis serve as the catalyst for DPS pyrolysis and Si catalytic growth. The use of Sn atomic cluster catalysts alters the reaction pathway to avoid SiC generation and enable formation of Si NDs with reduced dimensions. A typical Si NDsâC framework demonstrates a remarkable comprehensive performance comparable to other Si-based high-performance half LIBs, and higher energy densities compared to commercial full LIBs, as a consequence of the high dispersity of Si NDs with low lithiation stress. Supported by mechanic simulations, this study paves the way for construction of Si/C composites suitable for applications in future energy technologies.
RESUMEN
Interfacial engineering plays an important role in tuning the intrinsic property of electrode materials for energy applications such as lithium-ion batteries (LIBs), which however is rarely realized to amorphous electrode materials, despite a set of characteristics of amorphous materials desirable for LIBs. Here, Au atomic cluster layer-interfaced amorphous porous CoSnO3 nanocubes were fabricated by galvanic replacement and employed as a superior LIB anode, showing high reversible capacity (1615 mAh g-1 at 0.2 A g-1), good rate capability (1059 mAh g-1 with a 61.3% capacity retention upon the dramatic current variation from 0.1 to 5 A g-1), and excellent cycling stability. The amorphous nature, interconnected mesopores, and especially the thin Au atomic cluster layer on the surface/pore walls of CoSnO3 nanocubes can not only improve electron transport and ion diffusion in the electrode and electrolyte but also release the volume strain. Most significantly, density functional theory calculations reveal that the CoSnO3â¥Au heterointerface can induce the atomic polarization of CoSnO3 and lower Li ion diffusion barriers in CoSnO3 near the heterointerface, endowing it with a significantly enhanced theoretical lithium storage capacity and outstanding rate capability. This study provides a model of a heterointerface for amorphous materials with desired properties for high-performance LIBs and future energy applications.
RESUMEN
In this research, extraction optimization, preliminary characterization and immunological activities in vitro of polysaccharides from Elaeagnus angustifolia L. pulp were investigated. A response surface methodology (RSM) with a Box-Behnken design (BBD) was used to optimize the extraction process. The maximum EAP yield was 9.82±0.38%, which is in good agreement with the predicted value (9.93±0.24%). Two homogeneous polysaccharides, EAP-1a and EAP-1b with molecular weights of 8.70kDa and 4.39kDa respectively, were prepared by DEAE-52 cellulose and Sephadex G-100 columns and characterized by HPLC, HPGPC, and FT-IR. Three polysaccharides (EAP, EAP-1a and EAP-1b) could stimulate macrophages to release NO and enhance phagocytic activities of RAW 264.7 cells in dose-dependent manner. Moreover, there was no significant difference between crude EAP group (400µg/mL) and positive control group (LPS) in effects on macrophages. The results implied that EAP had the potential to be developed as natural medicines or health foods.
