Lithium-ion-conducting solid electrolytes hold promise for enabling high-energy battery chemistries and circumventing safety issues of conventional lithium batteries. Achieving the combination of high ionic conductivity and a broad electrochemical window in solid electrolytes is a grand challenge for the synthesis of battery materials. Herein we show an enhancement of the room-temperature lithium-ion conductivity by 3 orders of magnitude through the creation of nanostructured Li(3)PS(4). This material has a wide electrochemical window (5 V) and superior chemical stability against lithium metal. The nanoporous structure of Li(3)PS(4) reconciles two vital effects that enhance the ionic conductivity: (1) the reduction of the dimensions to a nanometer-sized framework stabilizes the high-conduction β phase that occurs at elevated temperatures, and (2) the high surface-to-bulk ratio of nanoporous β-Li(3)PS(4) promotes surface conduction. Manipulating the ionic conductivity of solid electrolytes has far-reaching implications for materials design and synthesis in a broad range of applications, including batteries, fuel cells, sensors, photovoltaic systems, and so forth.
A correlation between the electron spin-orbital angular momentum coupling and the superparamagnetic properties has been established in MgFe 2 O 4 and CoFe 2 O 4 spinel ferrite nanoparticles. The contribution to the magnetic anisotropy from the Fe 3+ lattice sites is almost the same in both nanocrystallites as neutron diffraction studies have shown a similar cation distribution in these two types of spinel ferrite nanoparticles. Due to the strong magnetic couplings from Co 2+ lattice sites, the blocking temperature of CoFe 2 O 4 nanoparticles is at least 150 deg higher than the same sized MgFe 2 O 4 nanoparticles. Mo ¨ssbauer spectroscopy studies demonstrate that the magnetic anisotropy of CoFe 2 O 4 nanoparticles is higher than that of the same size MgFe 2 O 4 nanoparticles. These studies indicate that the superparamagnetic properties of nanoparticles can be controlled through chemically adjusting the magnetic anisotropy energy.
Though carbon dioxide is a waste product of combustion, it can also be a potential feedstock for the production of fine and commodity organic chemicals provided that an efficient means to convert it to useful organic synthons can be developed. Herein we report a common element, nanostructured catalyst for the direct electrochemical conversion of CO 2 to ethanol with high Faradaic efficiency (63 % at À1.2 V vs RHE) and high selectivity (84 %) that operates in water and at ambient temperature and pressure. Lacking noble metals or other rare or expensive materials, the catalyst is comprised of Cu nanoparticles on a highly textured, N-doped carbon nanospike film. Electrochemical analysis and density functional theory (DFT) calculations suggest a preliminary mechanism in which active sites on the Cu nanoparticles and the carbon nanospikes work in tandem to control the electrochemical reduction of carbon monoxide dimer to alcohol.
MnFe2O4 nanoparticles are synthesized by using sodium dodecylbenzenesulfonate (NaDBS) to form water-in-toluene reverse micelles. The nanoparticles are single crystalline, and the average particle size can be
controlled from 4 to 15 nm. High- and low-resolution transmission electron microscopy characterization has
shown that the nanoparticles can have a size distribution as narrow as ∼9%. Neutron diffraction and magnetic
measurements have been conducted on the nanoparticles with a diameter of 7.7 ± 0.7 nm. The results
unambiguously prove that these MnFe2O4 nanoparticles are truly superparamagnetic. The synthesis and
characterization of these nanoparticles will facilitate the development of MnFe2O4 nanoparticles for the potential
applications such as contrast enhancement agents of magnetic resonance imaging and magnetic carriers for
site-specific drug delivery.
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