Quantification of the Carbon-Coating Effect on the Interfacial Behavior of Graphite Single Particles.

The effect of carbon coating on the interfacial charge transfer resistance of natural graphite (NG) was investigated by a single-particle measurement. The microscale carbon-coated natural graphite (NG@C) particles were synthesized by the simple wet-chemical mixing method using a phenolic resin as the carbon source. The electrochemical test results of NG@C using the conventional composite electrodes demonstrated desirable rate capability, cycle stability, and enhanced kinetic property.

Dual additive of lithium titanate and sulfurized pyrolyzed polyacrylonitrile in sulfur cathode for high rate performance in lithium-sulfur battery.

Lithium-Sulfur (Li-S) batteries have attracted much attention as next-generation batteries due to their high theoretical energy density. However, lithium polysulfide generated during the discharge loses intimate electrical contact with the carbon matrix due to its high solubility in the electrolyte, causing a high charge transfer resistance and slow redox kinetics for the discharge reactions, resulting in a low rate capability. A cathode additive having a strong chemical adsorbing site toward the polysulfide can effectively inhibit their dissolution.

Effect of a layer-by-layer assembled ultra-thin film on the solid electrolyte and Li interface.

Advanced all-solid-state batteries are considered as the most preferable power source for the next generation devices. Such batteries demand consumption of electrode materials with high energy and power density. One of the excellent solutions is the utilization of Li metal as anode which provides opportunity to fulfill such requirements.

Degradation Mechanism of All-Solid-State Li-Metal Batteries Studied by Electrochemical Impedance Spectroscopy.

Solid-state Li-metal batteries have the potential to achieve both high safety and high energy densities. Among various solid-state fast-ion conductors, the garnet-type LiLaZrO (LLZO) is one of the few that are stable to Li metal. However, the large interfacial resistance between LLZO and cathode materials severely limits the practical application of LLZO.

Phenylphosphonate surface functionalisation of MgMnO with 3D open-channel nanostructures for composite slurry-coated cathodes of rechargeable magnesium batteries operated at room temperature.

Spinel-type MgMnO, prepared by a propylene-oxide-driven sol-gel method, has a high surface area and structured bimodal macro- and mesopores, and exhibits good electrochemical properties as a cathode active material for rechargeable magnesium batteries. However, because of its hydrophilicity and significant water adsorption properties, macroscopic aggregates are formed in composite slurry-coated cathodes when 1-methyl-2-pyrrolidone (NMP) is used as a non-aqueous solvent. Functionalising the surface with phenylphosphonate groups was found to be an easy and effective technique to render the structured MgMnO hydrophobic and suppress aggregate formation in NMP-based slurries.

Ionic liquid-containing cathodes empowering ceramic solid electrolytes.

Although ceramic solid electrolytes, such as LiLaZrO (LLZO), are promising candidates to replace conventional liquid electrolytes for developing safe and high-energy-density solid-state Li-metal batteries, the large interfacial resistance between cathodes and ceramic solid electrolytes severely limits their practical application. Here we developed an ionic liquid (IL)-containing while nonfluidic quasi-solid-state LiCoO (LCO) composite cathode, which can maintain good contact with an Al-doped LLZO (Al-LLZO) ceramic electrolyte. Accordingly the interfacial resistance between LCO and Al-LLZO was significantly decreased.

Characterization of the Depth of Discharge-Dependent Charge Transfer Resistance of a Single LiFePO Particle.

The discharged state affects the charge transfer resistance of lithium-ion secondary batteries (LIBs), which is referred to as the depth of discharge (DOD). To understand the intrinsic charge/discharge property of LIBs, the DOD-dependent charge transfer resistance at the solid-liquid interface is required. However, in a general composite electrode, the conductive additive and organic polymeric binder are unevenly distributed, resulting in a complicated electron conduction/ion conduction path.

Low-Refractive-Index Deep-Ultraviolet Transparent Poly(fluoroalkyl--methylsilsesquioxane) Resins Synthesized by Cosolvent-Free Hydrolytic Polycondensation of Organotrimethoxysilanes.

Cosolvent-free (solventless) hydrolytic polycondensation of fluoroalkyltrimethoxysilanes of linear fluoroalkyl groups of the form R = CFCH ( = 1, 4, and 8) and methyltrimethoxysilane followed by thermal curing yielded dense polymeric silsesquioxane (SQ) resins with low refractive indices and deep-ultraviolet transparency with an ultraviolet absorption edge at ∼210 nm. The refractive index at 589 nm was adjustable at ∼1.35-1.

Structure Design of Long-Life Spinel-Oxide Cathode Materials for Magnesium Rechargeable Batteries.

Development of metal-anode rechargeable batteries is a challenging issue. Especially, magnesium rechargeable batteries are promising in that Mg metal can be free from dendrite formation upon charging. However, in case of oxide cathode materials, inserted magnesium tends to form MgO-like rocksalt clusters in a parent phase even with another structure, which causes poor cyclability.

Determining Factor on the Polarization Behavior of Magnesium Deposition for Magnesium Battery Anode.

To clarify the origin of the polarization of magnesium deposition/dissolution reactions, we combined electrochemical measurement, soft X-ray absorption spectroscopy ( SXAS), Raman, and density functional theory (DFT) techniques to three different electrolytes: magnesium bis(trifluoromethanesulfonyl)amide (Mg(TFSA))/triglyme, magnesium borohydride (Mg(BH))/tetrahydrofuran (THF), and Mg(TFSA)/2-methyltetrahydrofuran (2-MeTHF). Cyclic voltammetry revealed that magnesium deposition/dissolution reactions occur in Mg(TFSA)/triglyme and Mg(BH)/THF, while the reactions do not occur in Mg(TFSA)/2-MeTHF. Raman spectroscopy shows that the [TFSA] in the Mg(TFSA)/triglyme electrolyte largely does not coordinate to the magnesium ions, while all of the [TFSA] in Mg(TFSA)/2-MeTHF and [BH] in Mg(BH)/THF coordinate to the magnesium ions.

Twinning by Merohedry and Thermal Expansion of Zeolitic Clathrasil Deca-dodecasil 3R.

Rhombohedral crystal particles of zeolitic clathrasil deca-dodecasil 3R (DDR), hydrothermally synthesized from a mixture consisting of fumed silica, water, and 1-adamantanamine, were characterized by single-crystal and powder X-ray diffractometry as a function of temperature and pole figure analysis. The crystallite was bounded by six equivalent {101̅1} faces and exhibited twin-free appearance, whereas the structure was resolved with the binary twin by merohedry, defined by the twin point group 3̅2'/'1, consisting of two twin domains with nearly equal volume fractions. This twinning modifies the positions of O atoms in the Si-O-Si framework while preserving the positions of Si atoms that define the topology of polyhedral cages.

Ceramic-Based Flexible Sheet Electrolyte for Li Batteries.

The increasing demand for high-energy-density batteries stimulated the revival of research interest in Li-metal batteries. The garnet-type ceramic LiLaZrO (LLZO) is one of the few solid-state fast-ion conductors that are stable against Li metal. However, the densification of LLZO powders usually requires high sintering temperatures (e.

Cosolvent-free synthesis and characterisation of poly(phenyl-co-n-alkylsilsesquioxane) and poly(phenyl-co-vinylsilsesquioxane) glasses with low melting temperatures.

Thermoplastic poly(phenylsilsesquioxane) [poly(Ph-SQ)] and its copolymers with R-SQ units of linear aliphatic R groups [poly(Ph-co-R-SQ) (R = Me, Et, Pr, and Vi)] were synthesised by cosolvent-free hydrolytic polycondensation from acid-catalysed water-organotrimethoxysilane binary systems. These compounds became transparent glasses with coefficents of linear thermal expansion of ∼1 × 10-4 K-1 and Vickers hardnesses of 50-110 MPa when thermally treated at or above 100 °C. Poly(Ph-SQ) formed a fragile melt with kinetic fragility (F1/2 ⪆ 0.

Magnesium Storage Performance and Mechanism of 2D-Ultrathin Nanosheet-Assembled Spinel MgIn S Cathode for High-Temperature Mg Batteries.

Magnesium batteries have the potential to be a next generation battery with large capability and high safety, owing to the high abundance, great volumetric energy density, and reversible dendrite-free capability of Mg anodes. However, the lack of a stable high-voltage electrolyte, and the sluggish Mg-ion diffusion in lattices and through interfaces limit the practical uses of Mg batteries. Herein, a spinel MgIn S microflower-like material assembled by 2D-ultrathin (≈5.

Long-Term Stable Lithium Metal Anode in Highly Concentrated Sulfolane-Based Electrolytes with Ultrafine Porous Polyimide Separator.

Highly concentrated solutions composed of lithium bis(fluorosulfonyl)imide (LiFSI) and sulfolane (SL) are promising liquid electrolytes for lithium metal batteries because of their high anodic stability, low flammability, and high compatibility with lithium metal anodes. However, it is still challenging to obtain the stable lithium metal anodes in the concentrated electrolytes due to their poor wettability to the conventional polyolefin separators. Here, we report that the highly concentrated 1:2.

Modifications in coordination structure of Mg[TFSA]-based supporting salts for high-voltage magnesium rechargeable batteries.

To achieve a sustainable-energy society in the future, next-generation highly efficient energy storage technologies, particularly those based on multivalent metal negative electrodes, are urgently required to be developed. Magnesium rechargeable batteries (MRBs) are promising options owing to the many advantageous chemical and electrochemical properties of magnesium. However, the substantially low working voltage of sulfur-based positive electrodes may hinder MRBs in becoming alternatives to current Li-ion batteries.

Computational investigation of the Mg-ion conductivity and phase stability of MgZr(PO).

Solid electrolyte materials exhibiting high Mg-ion conductivity are required to develop Mg-ion batteries. In this study, we focused on a Mg-ion-conducting solid phosphate based electrolyte, MgZr(PO) (MZP), and evaluated the ionic conductivity of NASICON-type and β-iron sulfate-type MgZr(PO) structures density functional theory calculations. The calculations suggest that the migration energy of Mg is 0.

Phosphoric Acid Diethylmethylammonium Trifluoromethanesulfonate-Based Electrolytes for Nonhumidified Intermediate Temperature Fuel Cells.

The present study reports a new series of electrolytes for nonhumidified intermediate temperature fuel cells (IT-FCs). This series of new mixed electrolytes, composed of phosphoric acid (PA) and diethylmethylammonium trifluoromethanesulfonate ([dema][TfO]), was designed as nonhumidified IT-FC electrolytes. The mixed electrolytes show a higher thermal stability than pure PA, which is dehydrated at ITs.

Sol-gel-derived transparent silica-(Gd,Pr)PO glass-ceramic narrow-band UVB phosphors.

Silica-based monolithic transparent glass-ceramics containing (Gd,Pr)PO4 orthophosphate nanocrystals, prepared by a cosolvent-free sol-gel method, efficiently emit narrow-band ultraviolet B (UVB) photoluminescence (PL) at ∼313 nm from the 6P7/2 → 8S7/2 transition of Gd3+ ions upon excitation into the 4f-5d transition of Pr3+ ions. The formation of (Gd,Pr)PO4 nanocrystals as small as ∼5-10 nm facilitates energy transfer between rare-earth (RE) ions while avoiding optical loss by Rayleigh scattering. Unlike conventional phosphors, the aggregation of Gd3+ ions causes no concentration quenching, and the incorporation of inert RE ions to block energy transfer, such as La3+ and Y3+ ions, is unnecessary.

Poly(n-alkylsilsesquioxane) liquids prepared by cosolvent-free hydrolytic polycondensation of n-alkyltrialkoxysilanes: effects of liquid-liquid phase separation during aging and alkyl chain length on structure and viscosity.

The effect of the alkyl chain length and alkoxy groups on the viscosity and related properties of polysilsesquioxanes (PSQs) prepared by cosolvent-free hydrolytic polycondensation from n-alkyltrialkoxysilane-water binary systems via aging was investigated. n-Alkyltrialkoxysilanes with ethyl, n-propyl, and n-butyl groups gave PSQ liquids, whereas those with methyl groups yielded gels. The viscosity of the PSQ liquids remained stable over a month at room temperature despite the presence of many SiOH groups, and decreased with an increase in the alkyl chain length.

Good Low-Temperature Properties of Nitrogen-Enriched Porous Carbon as Sulfur Hosts for High-Performance Li-S Batteries.

Despite the increased attention devoted to exploring cathode construction based on various nitrogen-enriched carbon scaffolds at room temperature, the low-temperature behaviors of Li-S cathodes have yet to be studied. Herein, we demonstrate the good low-temperature electrochemical performances of nitrogen-enriched carbon/sulfur composite cathodes. Electrochemical evaluation indicates that a reversible capacity of 368 mAh g(-1) (0.

Synthesis of silanol-rich long-life polysilsesquioxane liquids by cosolvent-free hydrolytic polycondensation of organotrimethoxysilanes followed by aging.

Polysilsesquioxane (PSQ) liquids have been prepared from propyltrimethoxysilane-water and trimethoxy(3-sulfanylpropyl)silane-water binary systems without the use of organic solvents through hydrolytic polycondensation followed by aging. By introducing the aging step, the viscosity of the as-prepared PSQ liquid is decreased by more than an order of magnitude, and the long-term viscosity stability is improved considerably. These variations are mainly attributed to the modification of the topology of the Si-O-Si network because the crosslinking density was influenced little by the aging.

Nanoscale visualization of redox activity at lithium-ion battery cathodes.

Intercalation and deintercalation of lithium ions at electrode surfaces are central to the operation of lithium-ion batteries. Yet, on the most important composite cathode surfaces, this is a rather complex process involving spatially heterogeneous reactions that have proved difficult to resolve with existing techniques. Here we report a scanning electrochemical cell microscope based approach to define a mobile electrochemical cell that is used to quantitatively visualize electrochemical phenomena at the battery cathode material LiFePO4, with resolution of ~100 nm.

Characteristic coordination structure around Nd Ions in sol-gel-derived Nd-Al-codoped silica glasses.

Al codoping can improve the poor solubility of rare-earth ions in silica glasses. However, the mechanism is not well understood. The coordination structure around Nd ions in sol-gel-derived Nd-Al-codoped silica glasses with different Al content was investigated by optical and pulsed electron paramagnetic resonance spectroscopies.

Dermal administration of manganese porphyrin by iontophoresis.

The present study describes a technique for dermal administration of cationic manganese porphyrin (Mn-porphyrin), an antioxidant with superoxide dismutase (SOD) activity, in hairless mouse. In general, the stratum corneum on the surface of the skin represents a barrier to passive diffusion of therapeutic agents by standard dermal administration. The present study investigated whether, dermal administration of Mn-porphyrin solution using iontophoresis, the electrical dermal administration technique, could overcome this barrier.