Characterization and Comparative Study of Energy Efficient Mechanochemically Induced NASICON Sodium Solid Electrolyte Synthesis

In recent years, there is growing interest in solid-state electrolytes due to their many promising properties, making them key to the future of battery technology. This future depends among other things on easy processing technologies for the solid electrolyte. The sodium superionic conductor (NASICON) Na3Zr2Si2PO12 is a promising sodium solid electrolyte; however, reported methods of synthesis are time consuming. To this effect, attempt was made to develop a simple time efficient alternative processing route. Firstly, a comparative study between a new method and commonly reported methods was carried out to gain a clear insight into the mechanism of formation of sodium superionic conductors (NASICON). It was observed that through a careful selection of precursors, and the use of high-energy milling (HEM) the NASICON conversion process was enhanced and optimized, this reduces the processing time and required energy, opening up a new alternative route for synthesis. The obtained solid electrolyte was stable during Na cycling vs. Na-metal at 1 mA cm−1, and a room temperature conductivity of 1.8 mS cm−1 was attained

Synthesis and Characterization of a Multication Doped Mn Spinel, LiNi0.3_{0.3}Cu0.1_{0.1}Fe0.2_{0.2}Mn1.4_{1.4}O4_{4}, as 5 V Positive Electrode Material

The suitability of multication doping to stabilize the disordered Fd3̅m structure in a spinel is reported here. In this work, LiNi$_{0.3}$Cu$_{0.1}$Fe$_{0.2}$Mn$_{1.4}$O$_{4}$ was synthesized via a sol–gel route at a calcination temperature of 850 °C. LiNi$_{0.3}$Cu$_{0.1}$Fe$_{0.2}$Mn$_{1.4}$O$_{4}$ is evaluated as positive electrode material in a voltage range between 3.5 and 5.3 V (vs Li$^{+}$/Li) with an initial specific discharge capacity of 126 mAh g$^{-1}$ at a rate of C/2. This material shows good cycling stability with a capacity retention of 89% after 200 cycles and an excellent rate capability with the discharge capacity reaching 78 mAh g$^{-1}$ at a rate of 20C. In operando X-ray diffraction (XRD) measurements with a laboratory X-ray source between 3.5 and 5.3 V at a rate of C/10 reveal that the (de)lithiation occurs via a solid-solution mechanism where a local variation of lithium content is observed. A simplified estimation based on the in operando XRD analysis suggests that around 17–31 mAh g$^{-1}$ of discharge capacity in the first cycle is used for a reductive parasitic reaction, hindering a full lithiation of the positive electrode at the end of the first discharge

The Multisensor Array Based on Grown-On-Chip Zinc Oxide Nanorod Network for Selective Discrimination of Alcohol Vapors at Sub-ppm Range

We discuss the fabrication of gas-analytical multisensor arrays based on ZnO nanorods grown via a hydrothermal route directly on a multielectrode chip. The protocol to deposit the nanorods over the chip includes the primary formation of ZnO nano-clusters over the surface and secondly the oxide hydrothermal growth in a solution that facilitates the appearance of ZnO nanorods in the high aspect ratio which comprise a network. We have tested the proof-of-concept prototype of the ZnO nanorod network-based chip heated up to 400 °C versus three alcohol vapors, ethanol, isopropanol and butanol, at approx. 0.2–5 ppm concentrations when mixed with dry air. The results indicate that the developed chip is highly sensitive to these analytes with a detection limit down to the sub-ppm range. Due to the pristine differences in ZnO nanorod network density the chip yields a vector signal which enables the discrimination of various alcohols at a reasonable degree via processing by linear discriminant analysis even at a sub-ppm concentration range suitable for practical applications

Nanostructured Bifunctional Hydrogels as Potential Instructing Platform for Hematopoietic Stem Cell Differentiation

Hematopoietic stem cells (HSCs) are blood forming cells which possess the ability to differentiate into all types of blood cells. T cells are one important cell type HSCs can differentiate into, via corresponding progenitor cells. T cells are part of the adaptive immune system as they mediate cellular immune responses. Due to this crucial function, in vitro differentiated T cells are the subject of current studies in the biomedical field in terms of cell transplantation. Studies show that the density of the immobilized Notch ligand Delta-like 1 (DLL1) presented in HSCs' environment can stimulate their differentiation toward T cells. The development of reliable synthetic cell culture systems presenting variable densities of DLL1 is promising for the future expansion of T cells' clinical applications. Here we introduce bifunctional polyethylene glycol-based (PEG-based) hydrogels as a potential instructing platform for the differentiation of human hematopoietic stem and progenitor cells (HSPCs) to T cells. PEG hydrogels bearing the cell adhesion supporting motif RGD (arginyl-glycyl-aspartic acid) were synthesized by UV-light induced radical copolymerization of PEG diacrylate and RGD modified PEG acrylate. The hydrogels were furthermore nanostructured by incorporation of gold nanoparticle arrays that were produced by block copolymer micelle nanolithography (BCML). BCML allows for the decoration of surfaces with gold nanoparticles in a hexagonal manner with well-defined interparticle distances. To determine the impact of DLL1 density on the cell differentiation, hydrogels with particle distances of ~40 and 90 nm were synthesized and the gold nanoparticles were functionalized with DLL1. After 27 days in culture, HSPCs showed an unphysiological differentiation status and, therefore, the differentiation was evaluated as atypical T lymphoid differentiation. Cluster of differentiation (CD) 4 was the only tested T cell marker which was expressed clearly in all samples. Thus, although the applied nanopatterned hydrogels affected two important signaling pathways (integrins and Notch) for T cell differentiation, it appears that more functionalities that control T cell differentiation in nature need to be considered for achieving fully synthetic in vitro T cell differentiation strategies

Nanostructured Bifunctional Hydrogels as Potential Instructing Platform for Hematopoietic Stem Cell Differentiation

Hematopoietic stem cells (HSCs) are blood forming cells which possess the ability to differentiate into all types of blood cells. T cells are one important cell type HSCs can differentiate into, via corresponding progenitor cells. T cells are part of the adaptive immune system as they mediate cellular immune responses. Due to this crucial function, in vitro differentiated T cells are the subject of current studies in the biomedical field in terms of cell transplantation. Studies show that the density of the immobilized Notch ligand Delta-like 1 (DLL1) presented in HSCs' environment can stimulate their differentiation toward T cells. The development of reliable synthetic cell culture systems presenting variable densities of DLL1 is promising for the future expansion of T cells' clinical applications. Here we introduce bifunctional polyethylene glycol-based (PEG-based) hydrogels as a potential instructing platform for the differentiation of human hematopoietic stem and progenitor cells (HSPCs) to T cells. PEG hydrogels bearing the cell adhesion supporting motif RGD (arginyl-glycyl-aspartic acid) were synthesized by UV-light induced radical copolymerization of PEG diacrylate and RGD modified PEG acrylate. The hydrogels were furthermore nanostructured by incorporation of gold nanoparticle arrays that were produced by block copolymer micelle nanolithography (BCML). BCML allows for the decoration of surfaces with gold nanoparticles in a hexagonal manner with well-defined interparticle distances. To determine the impact of DLL1 density on the cell differentiation, hydrogels with particle distances of ~40 and 90 nm were synthesized and the gold nanoparticles were functionalized with DLL1. After 27 days in culture, HSPCs showed an unphysiological differentiation status and, therefore, the differentiation was evaluated as atypical T lymphoid differentiation. Cluster of differentiation (CD) 4 was the only tested T cell marker which was expressed clearly in all samples. Thus, although the applied nanopatterned hydrogels affected two important signaling pathways (integrins and Notch) for T cell differentiation, it appears that more functionalities that control T cell differentiation in nature need to be considered for achieving fully synthetic in vitro T cell differentiation strategies

Polyphthalaldehyde-block-polystyrene as a nanochannel template

A degradable polyphthalaldehyde-polystyrene block copolymer generated by modular ligation is reported for the first time serving as a nanochannel template for the formation of nanostructured materials. The polyphthalaldehyde- b-polystyrene copolymer was spin-coated onto a surface with subsequent polyphthalaldehyde block removal. Block conjugation and block removal were confirmed by H-NMR, SEC, AFM, and SEM. © the Partner Organisations 2014

Elucidating the energy storage mechanism of ZnMn2O4\mathrm{ZnMn_{2}O_{4}} as promising anode for Li-ion batteries

Tetragonal spinel ZnMn$_2$O$_4$ provides extremely high capacity as an anode for Li-ion batteries owing to a conversion-type mechanism. In this work, nanoparticle-composed layered ZnMn$_2$O$_4$ is synthesized using a co-precipitation method. Calcination parameters are optimized through thermal gravimetric analysis and in situ high temperature synchrotron X-ray powder diffraction. The ZnMn$_2$O$_4$ shows an initial lithiation capacity of ∼1400 mA h g$^{−1}$ and a high reversible capacity of ∼900 mA h g$^{−1}$ at a specific current of 0.5 A g$^{−1}$. In situ synchrotron X-ray powder diffraction reveals phase evolution during the 1st cycle. An intermediate phase, tetragonal spinel LiZnMn$_2$O$_4$, is formed and coexists with the original ZnMn$_2$O$_4$ during the 1st lithiation. Electrochemical impedance spectroscopy applied at varying potentials during the 1st cycle provides evidence of the high Li$^+$ diffusion coefficient and low resistance of the electrode in the lithiated state, which enables a high rate performance with 810 mA h g$^{−1}$ at 1 A g$^{−1}$ and 580 mA h g$^{−1}$ at 2 A g$^{−1}$. X-ray photoelectron spectroscopy reveals that the solid-electrolyte interphase is mainly composed of LiOH and Li$_2$CO$_3$, which can contribute additional capacity. In addition, an Mn(II)/Mn(III) redox reaction appearing during the 60th to 100th cycles is reported for the first time and could be another reason for the capacity increase upon cycling (the maximum capacity is ∼1250 mA h g$^{−1}$ at the 90th cycle). This redox reaction is facilitated by the increase in the electronic conductivity upon cycling. Based on these investigations, fundamental insights into the energy storage mechanism of ZnMn$_2$O$_4$ conversion anodes in Li-ion batteries are clarified. This work can shed light on an understanding of other conversion-type electrode materials

A facile route to boronic acid functional polymeric microspheres via epoxide ring opening

Boronic acid-functionalized microspheres are prepared for the first time via mild epoxide ring opening based on porous cross-linked polymeric microspheres (diameter similar to 10 mu m, porosity similar to 1000 angstrom). Quantitative chemical analysis by XPS and EA evidences that there is a greater functionalization with boronic acid when employing a sequential synthetic method [1.7 atom% boron (XPS); 1.12 wt% nitrogen (EA)] versus a one-pot synthetic method [0.2 atom% boron (XPS); 0.60 wt% nitrogen (EA)] yielding grafting densities ranging from approximately 2.5 molecules of boronic acid per nm2 to 1 molecule of boronic acid per nm2, respectively. Furthermore, the boronic acid-functionalized microspheres are conjugated with a novel fluorescent glucose molecule demonstrating a homogeneous spatial distribution of boronic acid

Access to intrinsically glucoside-based microspheres with boron affinity

Intrinsically glucoside-based microspheres are prepared in olive oil via a water in oil inverse suspension polymerization. The microspheres are characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) microscopy, and X-ray photoelectron spectroscopy (XPS), evidencing the intrinsic glucose character of the spheres. A novel boronic acid fluorescent molecule was subsequently conjugated to the microspheres in an aqueous environment, exhibiting the spatial and uniform distribution of glucoside as well as the affinity of the microspheres to bind with boron, evidenced via fluorescence spectroscopy measurements