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The switching performance of W/VO2 nanoparticles in thermochromic glass laminates was investigated. W/VO2 powder was prepared, and displayed a phase transition temperature and switching enthalpy of 20.9 degrees C and 37.5 +/- 0.2 J g- 1, respectively. Using wet bead milling, the particle size was reduced from 24 +/- 2 mu m to 120 +/- 10 nm. In the same process, the switching enthalpy decreased to 18.2 +/- 0.6 J g-1 due to partial loss of crystallinity. The kinetics of the structural phase transition were studied using Friedman's differential isoconversional method. This demonstrated that the activation energy |E alpha| was inversely proportional to the square of the difference between the material's temperature and the critical switching temperature T0, pointing out that nucleation kinetics were determining the rate. Furthermore, |E alpha| decreased upon milling, and kinetic asymmetry was induced. The milled nanoparticles were compounded with PVB to produce thermo-chromic films, which were applied for laminating glass plates. The impact of nanoparticle size and concentration on the resulting optical properties of the laminate, viz. solar transmission and solar modulation, was studied in detail. The highest solar modulation obtained was 9.4%. The results obtained in this study are of direct importance for the application in smart windows, showing that (i) the W/VO2 particle size needs to be

Co-free Li-rich layered oxides are gaining interest as feasible positiveelectrode materials in lithium-ion batteries (LIBs) in terms of energy density, costreduction, and alleviating safety concerns. Unfortunately, their commercialization ishindered by severe structural degradation that occurs during electrochemical operation.The study at hand demonstrates advanced structural engineering of a Li-rich Co-freeoxide with composition Li1.1Ni0.35Mn0.55O2by spray pyrolysis and subsequentcalcination of an aqueous precursor, creating a segregated structure of two distinctlayered phases with space groupsR3??m(rhombohedral) andC2/m(monoclinic). Thisparticular structure was investigated with powder neutron diffraction, high-resolutionanalytical transmission electron microscopy imaging, and electron energy loss spectroscopic characterization. This complex structurecontributes to the high electrochemical stability and good rate capability observed for this compound (160 mAh/g at C/3 and 100mAh/g at 1C).These results provide new insights into the feasibility of developing and commercializing cobalt-free positiveelectrode materials for LIBs The authors acknowledge funding from Generalitat de Catalunya 2017 SGR 1246 and 2017 SGR 327 and the Spanish MINECO project ENE2017-85087-C3 and PID2020- 116093RB-C43 / AEI / 10.13039/501100011033. IREC is funded by the CERCA Programme/Generalitat de Catalunya. IREC also acknowledges additional support from the European Regional Development Funds (ERDF, FEDER). This research was funded by HORIZON 2020-supported EU project COBRA, grant number H2020-EU.3.4.-875568. The authors also acknowledge Stephen Hull and Ron Smith for collecting neutron data at the ISIS neutron and the muon source using rapid access. The experiment number was 2000189.

Quasi-spherical undoped ZnO and Al-doped ZnO nanoparticles with different aluminum content, ranging from 0.5 to 5 at% of Al with respect to Zn, were synthesized. These nanoparticles were evaluated as photocatalysts in the photodegradation of the Rhodamine B (RhB) dye aqueous solution under UV-visible light irradiation. The undoped ZnO nanopowder annealed at 400 °C resulted in the highest degradation efficiency of ca. 81% after 4 h under green light irradiation (525 nm), in the presence of 5 mg of catalyst. The samples were characterized using ICP-OES, PXRD, TEM, FT-IR, 27Al-MAS NMR, UV-Vis and steady-state PL. The effect of Al-doping on the phase structure, shape and particle size was also investigated. Additional information arose from the annealed nanomaterials under dynamic N2 at different temperatures (400 and 550 °C). The position of aluminum in the ZnO lattice was identified by means of 27Al-MAS NMR. FT-IR gave further information about the type of tetrahedral sites occupied by aluminum. Photoluminescence showed that the insertion of dopant increases the oxygen vacancies reducing the peroxide-like species responsible for photocatalysis. The annealing temperature helps increase the number of red-emitting centers up to 400 °C, while at 550 °C, the photocatalytic performance drops due to the aggregation tendency. Funding: This research was co-funded by Hasselt University and Namur University through the BOF programme (Project R-9087) and the Fonds spécial de recherche. This work is also supported by the Research Foundation Flanders (FWO) and Hasselt University via the Hercules project AUHL/15/2-GOH3816N. This research used resources of the PC2 and the MORPH-IM platforms located at the University of Namur Acknowledgments: The authors acknowledge C. Charlier for his assistance with TEM and N. Billiet with N. Debusschere for the PXRD measurements.

Sulfur particles with a conductive polymer coating of poly(3,4-ethylene dioxythiophene) "PEDOT" were prepared by dielectric barrier discharge (DBD) plasma technology under atmospheric conditions (low temperature, ambient pressure). We report a solvent-free, low-cost, low-energy-consumption, safe, and low-risk process to make the material development and production compatible for sustainable technologies. Different coating protocols were developed to produce PEDOT-coated sulfur powders with electrical conductivity in the range of 10-8-10-5 S/cm. The raw sulfur powder (used as the reference) and (low-, optimum-, high-) PEDOT-coated sulfur powders were used to assemble lithium-sulfur (Li-S) cells with a high sulfur loading of ∼4.5 mg/cm2. Long-term galvanostatic cycling at C/10 for 100 cycles showed that the capacity fade was mitigated by ∼30% for the cells containing the optimum-PEDOT-coated sulfur in comparison to the reference Li-S cells with raw sulfur. Rate capability, cyclic voltammetry, and electrochemical impedance analyzes confirmed the improved behavior of the PEDOT-coated sulfur as an active material for lithium-sulfur batteries. The Li-S cells containing optimum-PEDOT-coated sulfur showed the highest reproducibility of their electrochemical properties. A wide variety of bulk and surface characterization methods including conductivity analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and NMR spectroscopy were used to explain the chemical features and the superior behavior of Li-S cells using the optimum-PEDOT-coated sulfur material. Moreover, postmortem [SEM and Brunauer-Emmett-Teller (BET)] analyzes of uncoated and coated samples allowed us to exclude any significant effect at the electrode scale even after 70 cycles.

We introduce an efficient framework for investigating the heterogeneity in battery porous electrodes and its impacts on the performance and longevity of lithium-ion batteries. A phenomenological pi...

Plasmon catalysis is an interesting technology concept for powering chemical processes with light. Here, we report the use of various Al2O3-supported Ru spheroidal nanoparticles as catalyst for the low-temperature conversion of CO(2)and H(2)to CH4(Sabatier reaction), using sunlight as energy source. At high loadings of Ru spheroidal nanoparticles (5.9 % w/w), we observe a sharp increase in the rate of the sunlight powered reaction when compared to the reaction in dark at the same catalyst bed temperature. Based on our results we exclude plasmon coupling as cause, and attribute the rate enhancement to collective photothermal heating of the Al2O3-supported Ru nanoparticles. R.H., J.R., F.S., N.M., M.X., P.B. (all TNO), K.E. (IMEC), A.H., M.K.V.B. (both Hasselt University) and T.d.H. (Zuyd University of Applied Sciences) acknowledge financial support from the European Fund for Regional Development through the cross-border collaborative Interreg V program Flanders-The Netherlands (project LUMEN), co-financed by the Belgian province of Limburg and the Dutch provinces of Limburg and Noord-Brabant. M.A.V. acknowledges Solliance and the Dutch province of Noord-Brabant for funding the TEM facility. den Hartog, T; Buskens, P (corresponding author), Netherlands Org Appl Sci Res TNO, High Tech Campus 25, NL-5656 AE Eindhoven, Netherlands ; Zuyd Univ Appl Sci, Appl Sci Acad, Nieuw Eyckholt 300, NL-6400 AN Heerlen, Netherlands ; Hasselt Univ, Inst Mat Res Design & Synth Inorgan Mat DESINe, Agoralaan Bldg D, B-3590 Diepenbeek, Belgium. tim.denhartog@tno.nl; pascal.buskens@tno.nl

A eutectic system is a mixture of two or more substances, displaying a melting temperature lower than its standalone components. The eutectic composition displays the lowest melting temperature of all mixtures. Typically, a eutectic system is used as an example of binary phase diagrams to demonstrate to undergraduate students. Herein, the liquidus and solidus define regions in the phase diagram where the mixture is either a liquid, a solid, or a combination of both. This experiment aims to construct the binary phase diagram of a mixture of menthol (M) and lauric acid (LA) by measuring the thermal properties of a wide range of compositions utilizing differential scanning calorimetry (DSC). The solidus and liquidus are uniquely located below room temperature. The eutectic melting temperature is around 12 °C, while the standalone menthol and lauric acid components melt at 36 and 48 °C, respectively. This allows the visual demonstration of the compositions in all of the defined regions in the binary phase diagram. Furthermore, the theory of cryoscopy is utilized to predict the liquidus of the phase diagram. The comparison with the experimentally determined melting temperatures allows the undergraduate students to reflect on the reliability of the derived equation.

The redox reaction between dioxovanadium(V) and oxalate is proposed as a suitable system to analyze the kinetics of a two-step reaction mechanism using UV–vis spectroscopy. First, the spectra of di...

This work introduces the polymeric eutectogel (P-ETG) solid composite electrolytes (SCEs) developed from the encapsula-tion of a liquid deep eutectic solvent (DES) electrolyte within a solid amide-...

The preparation of Ru nanoparticles supported on gamma-Al2O3 followed by chemical reduction using RuCl3 as a precursor is demonstrated, and their properties are compared to Ru nanoparticles supported on gamma-Al2O3 prepared by impregnation of gamma-Al2O3 with Ru-3(CO)(12) and subsequent thermal decomposition. The Ru nanoparticles resulting from chemical reduction of RuCl3 are slightly larger (1.2 vs. 0.8 nm). In addition, Ru nanoparticles were deposited on Stober SiO2 using both deposition techniques. These particles were larger than the ones deposited on gamma-Al2O3 (2.5 and 3.4 nm for chemical reduction and thermal decomposition, respectively). Taking into account the size differences between the Ru nanoparticles, all catalysts display similar activity (0.14-0.63 mol center dot g(Ru)(-1)center dot h(-1)) and selectivity (>= 99%) in the sunlight-powered Sabatier reaction. Ergo, the use of toxic and volatile Ru-3(CO)(12) can be avoided, since catalysts prepared by chemical reduction of RuCl3 display similar catalytic performance. This research was funded by the European Commission (H2020 project SPOTLIGHT, grant no. 722788).

The thermodynamics and kinetics of the structural phase transition from monoclinic VO2 (M) to rutile VO2 (R) and vice versa were studied for particulate materials obtained by bead milling of VO2 (M) powder. Using wet bead milling, we decreased the particle size of VO2 (M) powder from similar to 1 mu m to 129 nm. With progressive milling, the switching enthalpy decreased from 47 J g(-1) to 29 J g(-1) due to a loss of crystallinity. The switching kinetics were studied using Friedman's differential isoconversional method. The activation energy vertical bar E-alpha vertical bar decreases with increasing difference between the actual temperature of the material and its switching temperature (T-0). Furthermore, vertical bar E-alpha vertical bar decreases with progressive milling, and kinetic asymmetry is induced. For milled particulate materials, vertical bar E-alpha vertical bar is lower for the switch from VO2 (R) to VO2 (M) than for the opposite switch. For hydrothermally synthesized nanoparticles, vertical bar E-alpha vertical bar is in the same order of magnitude, albeit with inverse switching asymmetry. Latter may result from different defects that are introduced during both preparation techniques. Applying layers of milled particulate material to glass sheets yielded thermochromic coatings with luminous transmission of 40.7% and solar modulation of 8.3%. This demonstrates that milled VO2 particles have potential for use in energy efficient thermochromic windows. The authors thank NWO-SIA (RAAK-PRO project Window of the Future) for their financial support. The authors acknowledge financial support from the European Fund for Regional Development through the cross-border collaborative Interreg V program Flanders-The Netherlands (project SUNOVATE), co-financed by the Belgian province of Limburg and the Dutch provinces of Limburg and Noord-Brabant. Furthermore, the authors gratefully acknowledge Dr. Marcel Verheijen (Eindhoven University of Technology and Eurofins Materials Science) for the TEM analyses, Dr. Martijn Brouwer and Dr. Man Xu (both TNO) for the optical profilometry measurements and Dr. Marta Jezierska-Switala (TNO) for the XRD analyses.

Ni-rich layered lithium transition metal oxides (LiNi x Mn y Co z O 2) have gained significant attention as high-capacity positive electrode materials for lithium-ion batteries. However, their poor cyclability, capacity retention, and rate capability at higher working potentials limit their applications in commercial batteries. Here, we demonstrate a cost-effective chemical solution deposition route of a thin TiO x shell on LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NMC-622) particles and the effect of surface modification on the electrochemical properties. The crystallinity and morphology of the NMC-622 particles are unaffected by the deposition step and verified by powder X-ray diffraction and electron microscopy. High-resolution transmission electron microscopy (HR-TEM) and selected area electron diffraction (SAED) analysis showed that the TiO x surface layer is amorphous and prone to enhance the electronic conductivity of the cathode material. The TiO x-coated material has an improved rate performance and experiences a lower charge-transfer resistance compared to the pristine material. The effect of the surface modification on the electrochemical performance of NMC-622 was investigated further by the assembly of NMC-622/Li 4 Ti 5 O 12 (LTO) full cells. The beneficial impact of the TiO x coating on the electrochemical performance of NMC-622 positive electrodes in lithium-ion battery applications was showcased by the higher initial Coulombic efficiency and lower aging rates during 150 cycles at 1C in NMC-622/LTO cells.

The gradual loss of capacity and increase in the cell impedance are the mainstream of aging patterns for the lithium-ion batteries and mainly result from the depletion of cell’s cyclable-lithium reservoir. The irreversible drain from this reservoir is well understood and originates from the phenomena such as electrolyte oxidation and reduction at the electrode/electrolyte interfaces. There is, however, limited knowledge about the circumstances leading to the recuperation of misplaced lithium, gain in cell’s energy, and impedance drop. Here, we showcase that the intragranular fracture induces a peculiar aging behavior in the LiNi0.6Mn0.2Co0.2O2 electrodes. Fracture enables an alternative path for the (de)insertion of lithium from the hard-to-reach center of the secondary particles by lithium pore-wall flux instead of solid-state diffusion. The possible consequences are the energy recovery and decrease of the charge-transfer resistance in the electronically well wired electrodes.

[EN] The metastability impediment which usually prevents the obtaining of a phase-pure BiFeO3 material can be dramatically stressed when taking the system to the thin film configuration. In order to preserve the stoichiometry, the films need to be processed at low temperatures and hence the solid-state diffusion processes which usually govern the microstructural evolution in bulk cannot be expected to also rule the development of the functional films. All these circumstances were presumed when exploring the possibilities of an aqueous solution–gel process plus spin-coating deposition method to reproduce, in thin film dimensions, the excellent multiferroic properties that have been previously observed with an optimized rare-earth and Ti4+-codoped BiFeO3 bulk composition. The experiments indicate high reliability for the tested methodology, allowing for the obtaining of homogeneous dense films at temperatures as low as 600 1C and with a tunable multiferroic response depending on the formulated rare-earth (Sm or Nd). Thorough structural characterization of the films reveals that despite the low temperature processing restrictions, effective microstructural control is achieved at the nanoscale, which is attributed to effective retention (pinning) of the dopants inside the perovskite structure of BiFeO3., his work was supported by the Spanish Ministry of Science, Innovation and Universities (MICINN) under projects MAT2016-80182-R, MAT2017-87134-c2-2-R and partially by the project MAT2016-76851-R. It was also supported by the Research Foundation Flanders (FWO-Vlaanderen), project number G039414N. Dr T. Jardiel acknowledges the European Science Foundation (ESF) and the Ramon y Cajal Program of MICINN for the financial support. Work by Dr Calatayud was also supported by Fundación General CSIC (COMFUTURO Program). We acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI).

LiNi0.5Mn1.5 O4-δ (LNMO) is a potential candidate for high voltage Co-free cathodes in lithium-ion batteries. In this study, pre-calcination temperature, time, and oven type are showcased as important parameters influencing the particle size and morphology of the LNMO powder synthesized from the aqueous citric acid-acetates-NH3 based method. These parameters determine the amount of organic residues in the precursor powder. A superior initial discharge capacity and capacity retention are obtained by an optimum combination of the particle size and morphology for the Li|LNMO coin cells. Pre-calcination in a forced convection oven at 200 °C for 40 h results in a voluminous and foam-like LNMO precursor powder morphology with the lowest amount of organic residue, leading to a ~ 1–4 µm powder with well-defined facets. Applying 24 h pre-calcination at 170 °C in a natural convection oven results in large LNMO aggregates of ~ 70 µm. Ball-milling of the crystalline LNMO powder is effective to reduce the agglomeration and particle size but deteriorates the electrochemical performance. An initial discharge capacity of 121 mA h g-1 at 0.2 C and a capacity retention of 90% after 400 cycles at 2 C are obtained from the samples prepared by 40 h pre-calcination at 200 °C in a forced-convection oven.

Fast and scalable low-temperature deposition of microscale metallic features is of utmost importance for the development of future flexible smart applications including sensors, wireless communication, and wearables. Recently, a new class of metal−organic decomposition (MOD) copper inks was developed, consisting of self-reducing copper formate containing amine complexes. From these novel inks, copper metal features with outstanding electrical conductivity (±105 S cm−1 ) are deposited at a temperature of 150 °C or less, which is well below the reduction temperature of orthorhombic α-copper formate (around 225 °C). However, the underlying principle of this reaction mechanism and the relationship between the corresponding temperature shift and the amine coordination are still under debate. The current study provides a full explanation for the shift in reduction temperatures via in situ characterization. The results clearly indicate that the structural resemblance and stability of the Cu(II) starting compound and the occurring Cu(I) intermediate during the in situ reduction are the two main variables that rationalize the temperature shift. As such, the thermal compatibility of copper MOD inks with conventional plastic substrates such as polyethylene terephthalate can be explained, based on metal−organic complex properties. The authors acknowledge F. Mattelaer and C. De Tavernier from the COCOON group at Ghent University for the in situ HT-XRD measurements to support the findings based on the XAS data. Moreover, J. Maggen is acknowledged for performing the CHN analysis, B. Joos and G. Maino for the electrochemical experiments, and the DUBBLE and SOLEIL beamline staff for their support during and after the measurement campaigns. Moreover, this work was supported by a public grant overseen by the French National Research Agency (ANR) as part of the "Investissements d'Avenir" program (reference: ANR10-EQPX45). Prof. Van Hecke thanks the Hercules Foundation (project AUGE/11/029 "3D-SPACE: 3D Structural Platform Aiming for Chemical Excellence") and the Special Research Fund (BOF) UGent (project 01N03217) for funding. Finally, the authors are grateful for the SIM-Met@linkfunding.

Vertically aligned nitrogen-doped nanocrystalline diamond nanorods are fabricated from nitrogen-doped nanocrystalline diamond films using reactive ion etching in oxygen plasma. These nanorods show enhanced thermionic electron emission (TEE) characteristics, viz.. a high current density of 12.0 mA/cm(2) and a work function value of 4.5 eV with an applied voltage of 3 Vat 923 K. The enhanced TEE characteristics of these nanorods are ascribed to the induction of nanographitic phases at the grain boundaries and the field penetration effect through the local field enhancement from nanorods owing to a high aspect ratio and an excellent field enhancement factor.

One-dimensional diamond nanorods (DNRs) were fabricated from nanocrystalline diamond films using a facile combination of microwave plasma enhanced chemical vapor deposition and reactive ion etching (RIE) techniques. Structural and electrochemical properties of undoped and nitrogen doped DNRs were thoroughly investigated. A cyclic voltammetry study revealed the increase in density of charge carriers when doped with nitrogen. Mott Schottky analysis was implemented for the quantitative determination of the flat band potential, effective density of charge carriers and energy band diagram, which revealed that the undoped sample exhibit p-type behavior, whereas the nitrogen doped sample showed n-type behavior. Defect related damage due to graphitization and hydrogen termination in the undoped DNRs (during RIE) was correlated with the p-type conductivity. Nitrogen doping induces n-type conductivity and enhances effective density of charge carriers.

Thin orthorhombic ultra high- k LuFeO 3 (LFO) films on Si 3 N 4 /SiO 2 /Si substrates were obtained by means of aqueous chemical solution deposition (CSD). Prior to thin film deposition, the precursor synthesis, thermal decomposition and crystallization behavior of the bulk material were studied. It was shown that phase-pure hexagonal LFO powder could be formed at 650 °C while a higher temperature of 900 °C was required to obtain the orthorhombic phase. Deposition on SiO 2 /Si resulted in the development of silicates in this temperature range, thus preventing the formation of the orthorhombic LuFeO 3 phase. The use of Si 3 N 4 /SiO 2 /Si as the substrate shifted the silicate formation to higher temperature, allowing the synthesis of phase-pure orthorhombic LuFeO 3 as a thin film at 1000 °C. Impedance spectroscopy analyses confirmed its associated ultra high dielectric constant (>10,000) at room temperature for frequencies lower than or equal to 1 kHz.

Layered Li-rich/Mn-rich NMC (LMR-NMC) is characterized by high initial specific capacities of more than 250 mA h g(-1), lower cost due to a lower Co content and higher thermal stability than LiCoO2. However, its commercialisation is currently still hampered by significant voltage fade, which is caused by irreversible transition metal ion migration to emptied Li positionsviatetrahedral interstices upon electrochemical cycling. This structural change is strongly correlated with anionic redox chemistry of the oxygen sublattice and has a detrimental effect on electrochemical performance. In a fully charged state, up to 4.8 Vvs.Li/Li+, Mn4+ is prone to migrate to the Li layer. The replacement of Mn4+ for an isovalent cation such as Sn4+ which does not tend to adopt tetrahedral coordination and shows a higher metal-oxygen bond strength is considered to be a viable strategy to stabilize the layered structure upon extended electrochemical cycling, hereby decreasing voltage fade. The influence of Sn4+ on the voltage fade in partially charged LMR-NMC is not yet reported in the literature, and therefore, we have investigated the structure and the corresponding electrochemical properties of LMR-NMC with different Sn concentrations. We determined the substitution limit of Sn4+ in Li1.2Ni0.13Co0.13Mn0.54-xSnxO2 by powder X-ray diffraction and transmission electron microscopy to be x approximate to 0.045. The limited solubility of Sn is subsequently confirmed by density functional theory calculations. Voltage fade for x= 0 andx= 0.027 has been comparatively assessed within the 3.00 V-4.55 V (vs.Li/Li+) potential window, from which it is concluded that replacing Mn4+ by Sn4+ cannot be considered as a viable strategy to inhibit voltage fade within this window, at least with the given restricted doping level.

Monoclinic VO2 (M) displays thermochromic properties based on its reversible metal-insulator transition. We studied the kinetics of the underlying structural phase transition (SPT) from monoclinic VO2 (M) to rutile VO2 (R) and vice versa both in powders and coatings, using isoconversional kinetic analysis based on datasets obtained through differential scanning calorimetry and UV–vis–NIR spectrophotometry. For VO2 powders, prepared via solution-phase reduction of V2O5 with oxalic acid and subsequent thermal anneal, we show that the activation energy | E a | of the SPT is temperature dependent, and decreases with increasing difference between the material's temperature and the critical switching temperature T 0 . | E a | for both VO2 (M) to VO2 (R) and VO2 (R) to VO2 (M) is similar, and ranges between 138 and 563 kJ mol−1, depending on the temperature of the material. This indicates that similar defects play a key role in both SPTs. Upon doping with tungsten, T 0 was lowered from 66.93 °C (0 at. % W) to −28.38 °C (3.5 at. % W). | E a | , however, remained in the same range. Nonetheless, at W concentrations above 2 at. % a significant asymmetry was observed with higher | E a | for the switch from VO2 (R) to VO2 (M). The SPT of VO2 (M) in coatings proceeded 4 times slower. This may result from the immobilization of the VO2 domains on the substrate surface and within the coating network, making the SPT more difficult to progress. The findings of this study have important implications for the application of VO2 (M) in energy efficient thermochromic glazing.

Plasma catalysis, a promising technology for conversion of CO2 into value-added chemicals near room temperature, is gaining increasing interest. A dielectric barrier discharge (DBD) plasma has attracted attention due to its simple design and operation at near ambient conditions, ease to implement catalysts in the plasma zone and upscaling ability to industrial applications. To improve its main drawbacks, being relatively low conversion and energy efficiency, a packing material is used in the plasma discharge zone of the reactor, sometimes decorated by a catalytic material. Nevertheless, the extent to which different properties of the packing material influence plasma performance is still largely unexplored and unknown. In this study, the particular effect of synthesis induced differences in the morphology of a TiO2 shell covering a SiO2 core packing material on the plasma conversion of CO2 is studied. TiO2 has been successfully deposited around 1.6–1.8 mm sized SiO2 spheres by means of spray coating, starting from aqueous citratoperoxotitanate(IV) precursors. Parameters such as concentration of the Ti(IV) precursor solutions and addition of a binder were found to affect the shells’ properties and surface morphology and to have a major impact on the CO2 conversion in a packed bed DBD plasma reactor. Core-shell SiO2@TiO2 obtained from 0.25 M citratoperoxotitante(IV) precursors with the addition of a LUDOX binder showed the highest CO2 conversion 37.7% (at a space time of 70 s corresponding to an energy efficiency of 2%) and the highest energy efficiency of 4.8% (at a space time of 2.5 s corresponding to a conversion of 3%).

Deposition of functional materials on nonplanar surfaces remains a challenge for various applications, including three-dimensional (3D) all-solid-state Li-ion batteries. In this Letter we present a new process to deposit functional oxide materials on high aspect ratio microstructures without the use of vacuum-based deposition methods. Using ultrasonic spray deposition in combination with metal citrate chemistry, we were able to deposit high-quality coatings on Si microcylinders with an aspect ratio of 10. These results were achieved by controlling the precursor chemistry, wetting properties, gel mobility, and precursor decomposition. The versatility of the process was shown by depositing titanium oxide (TiO2), lithium lanthanum titanate (Li0.35La0.55TiO3), and tungsten oxide (WO3) on Si microcylinders of 50 μm length with an intercylinder distance of 5 μm. Finally, a proof of the 3D battery concept was achieved by coating of TiN/Si microcylinders with WO3 using a minimized thermal budget to preserve the (...

Hexagonal boron nitride nanowall thin films were deposited on Si(100) substrates using a Ar(51%)/N-2(44%)/H-2(5%) gas mixture by unbalanced radio frequency sputtering. The effects of various target-to-substrate distances, substrate temperatures, and substrate tilting angles were investigated. When the substrate is close to the target, hydrogen etching plays a significant role in the film growth, while the effect is negligible for films deposited at a farther distance. The relative quantity of defects was measured by a non-destructive infrared spectroscopy technique that characterized the hydrogen incorporation at dangling nitrogen bonds at defect sites in the deposited films. Despite the films deposited at different substrate tilting angles, the nanowalls of those films were found to consistently grow vertical to the substrate surface, independent of the tilting angle. This implies that chemical processes, rather than physical ones, govern the growth of the nanowalls. The results also reveal that the degree of nanowall crystallization is tunable by varying the growth parameters. Finally, evidence of hydrogen desorption during vacuum annealing is given based on measurements of infrared stretching (E-1u) and bending (A(2u)) modes of the optical phonons, and the H-N vibration mode.

Silver nanoparticle inkjet inks are commonly used to print electrically conductive patterns, such as sensors or electrodes in organic light emitting diodes (OLEDs) or organic photovoltaic devices (OPVs). After printing, a sintering step is required to transform the printed layer into an electrically conductive one. Gaining more insight into the occurring phenomena during this post-treatment step is necessary when applying different kinds of inkjet ink. Therefore, in this work the commercially available silver nanoparticle inkjet ink Metalon JS-B30G from Novacentrix is characterised during the different stages in the printing and thermal sintering sequence. The pre-printing and post-sintering characterisation proves that the inkjet ink used has got the right material parameters, such as viscosity and particle size. Silver layers with sheet resistances of 40 mΩ/sq were obtained with an average roughness lower than 10 nm. The experiments performed show the different stages during the thermal sintering procedure. Based on this, suitable thermal sintering parameters are defined leading to application of these conductive silver layers in OLEDs.

Sodium-ion batteries (SIBs) are a potential cost-effective alternative for lithium-ion batteries (LIBs) in applications which require large-scale energy storage. In these applications, low cost and sustainability are of prime importance. The extensive use of LIBs for large-scale storage would drive up lithium prices because of the latter’s limited production. As the lightest and smallest alkali metal after lithium, sodium is abundant and widely available, and is therefore more cost-efficient and sustainable. SIBs can use light and inexpensive aluminum current collectors for both the anode and cathode, as opposed to LIBs, which usually require more expensive copper current collectors for the anodes. This further increases the SIB's viability in applications where cost and sustainability are the most crucial factors. Viable battery electrolytes should have sufficient ionic conductivity, be electronically insulating, have a large electrochemical and thermal stability window, and not show reactivity with the other components of the battery. They should be safe, non-toxic, and inexpensive. Ionic liquids, defined as materials which consist entirely out of ions and which remain liquid below 100 °C, were previously studied as electrolytes for SIBs as they have a high intrinsic ionic conductivity, can dissolve high amounts of salt, are non-flammable and have a high thermal and (electro)chemical stability. Ionic liquids are typically expensive due the difficulty of their synthesis. Deep eutectic solvents (DESs) are closely related to ionic liquids and consist of a mixture of Lewis/Brönsted acids and bases, where the melting temperature of the mixture is below that of the individual components. Whereas DESs and ionic liquids can have similar physical properties, DESs can have additional advantages such as ease of preparation and wide availability of reagents, although this depends on the exact composition. Binary and ternary mixtures of different XFSI (FSI = bis(fluorosulfonyl)imide) and XTFSI (TFSI = bis(trifluoromethanesulfonyl)imide) inorganic salts were previously applied as DES electrolyte in sodium-ion half cells, which were constrained to operation at 80 °C or higher because of their relatively high melting points.1,2 These cells showed high reversibility and high Coulombic efficiency. Other DESs may also offer an increase of the stability of battery operation, and may be used at less stringent temperature conditions (with acceptable ionic conductivity even at room temperature). This stability problem is particularly pronounced at 55 °C or higher for conventional electrolytes, where battery performance rapidly degrades when linear carbonates are used as electrolyte solvent.3 Our series of DESs as SIB electrolytes were based on the dissolution of NaTFSI in an amide which is solid at room temperature. For each electrolyte, the effect of the solution structure on its electrochemical properties was studied. The amide was spontaneously reduced when contacted with sodium metal. By increasing the salt concentration, we observe a lower reactivity with sodium metal, a broader electrochemical stability window and a decreased ionic conductivity due to the strong Coulombic interactions among the amide molecules, Na+, and TFSI- ions (Figure). The sample containing 10 mol% of NaTFSI shows an anodic stability limit of ~3.6 V vs Na+/Na and a conductivity of 10.3 mS cm-1 at 55 °C. A DES with 30 mol% NaTFSI is stable up to ~4.6 V vs Na+/Na and has a conductivity of 3.8 mS cm-1 at 55 °C. The variation of conductivity with temperature of both DESs could be fitted with the Vogel-Tamman-Fulcher equation. At 55 °C, (Na3V2(PO4)3/C)/(Na2+x Ti4O9/C) full cells containing DES as electrolyte demonstrate a considerably higher durability and Coulombic efficiency than cells containing a conventional organic solvent-based electrolyte. As such, these DESs form a new class of electrolytes for application in sodium-ion batteries, offering a more durable performance at 55 °C than conventional systems. References (1) Nohira, T.; Ishibashi, T.; Hagiwara, R. Properties of an Intermediate Temperature Ionic Liquid NaTFSA – CsTFSA and Charge – Discharge Properties of NaCrO2 Positive Electrode at 423 K for a Sodium Secondary Battery. J. Power Sources 2012, 205, 506–509. (2) Fukunaga, A.; Nohira, T.; Kozawa, Y.; Hagiwara, R. Intermediate-Temperature Ionic Liquid NaFSA-KFSA and Its Application to Sodium Secondary Batteries. J. Power Sources 2012, 209, 52–56. (3) Yan, G.; Dugas, R.; Tarascon, J. The Na3V2(PO4)2F3/Carbon Na-Ion Battery: Its Performance Understanding as Deduced from Differential Voltage Analysis. J. Electrochem. Soc. 2018, 165 (2), 220–227. Figure 1

In this research work, three different polymers LiPAA, PVDF, and PEO were used as polymeric binders for the sulfur electrodes in Li–S cells. All electrodes had a high sulfur, loading ~4.0 mg per cm2. The coin-cells were characterized by EIS and tested by constant current cycling and cyclic voltammetry using a standard electrolytic solution of LiTFSI in an ether mixture with LiNO3 as additive. The cycled sulfur electrodes were characterized by post-mortem SEM and N2 -sorption and compared to the pristine states. LiPAA-based cells showed the highest reproducibility of the electrochemical performances, the most limited specific capacity fading (at least twice smaller), and the better rate capability compared to PVDF- and PEO-based cells. The electrochemical data agreed with the post-mortem analyses of the different electrodes. The pristine electrodes showed similar morphologies and porosities independent of the polymeric binder used. Dramatic changes were observed for the PEO- and PVDF-based sulfur electrodes, in which a new dense morphology appeared after two and thirty cycles, respectively. Both PEO- and PVDF-based cycled electrodes were prone to delaminate from the current collector. In comparison, the morphology of the LiPAA-based sulfur electrodes remained mostly unchanged even after thirty cycles and no delamination behavior could be observed.

The preparation of well-dispersed graphene/polymer nanocomposites is challenging due to the poor miscibility of graphene sheets in a polymer matrix. To enhance the interaction between both phases, graphene sheets can be decorated with polymer chains. Herein, different strategies to graft poly(methyl methacrylate) (PMMA) and poly(di(ethylene glycol) ethyl ether acrylate) (PDEGA) chains at various positions on graphene oxide and reduced graphene oxide (GO/rGO) sheets are compared. Chain attachment was achieved by “grafting-to” and “grafting-from” methods. Grafting-to was performed by classical copper (I)-catalyzed alkyne azide cycloaddition. Using a grafting-from approach, PMMA and PDEGA brushes were grown from GO and rGO sheets via surface-initiated photo-induced copper-mediated polymerization (SI-photoCMP). SI-photoCMP is a robust and efficient method that allows polymerizations to be carried out under mild conditions and with reduced catalyst concentration. Moreover, the successful implementation of SI-photoCMP in a continuous-flow set-up enables easy upscaling of the system and is, therefore, a more efficient and environmentally friendly process for GO/rGO surface modification. By using the grafting-to approach, the grafting density of PMMA (Mn = 2,600 g/mol) was one chain per 990 carbons of graphene. In contrast, longer PMMA chains (Mn = 40,300 g/mol) and higher grafting density were obtained via the grafting-from method (one PMMA chain per 140 carbons of graphene).