Fluoroethylene carbonate (FEC) and vinylene (VC) are widely used as electrolyte additives in lithium ion batteries. Here we analyze the solid interphase (SEI) formed on binder-free silicon nanowire (SiNW) electrodes pure FEC or VC electrolytes containing 1 M LiPF6 by solid-state NMR with without dynamic nuclear polarization (DNP) enhancement. We find that polymeric SEIs consist mainly of cross-linked poly(ethylene oxide) (PEO) aliphatic chain functionalities along additional carboxylate...

A novel route for the introduction of well-defined zinc species into ZSM-5 zeolite via chemical vapor deposition dimethylzinc (CVD(DMZ)) is explored. The structural properties and catalytic reactivity synthesized material (Zn/ZSM-5-CVD(DMZ)) are investigated against a set Zn/ZSM-5 catalysts prepared by incipient wetness impregnation (IWI), ion exchange (IE), high-temperature reaction with (CVD(m)). materials characterized range physicochemical methods including temperature programmed...

To elucidate the role of fluoroethylene carbonate (FEC) as an additive in standard carbonate-based electrolyte for Li-ion batteries, solid interphase (SEI) formed during electrochemical cycling on silicon anodes was analyzed with a combination solution and solid-state NMR techniques, including dynamic nuclear polarization. facilitate characterization via 1D 2D NMR, we synthesized 13C-enriched FEC, ultimately allowing detailed structural assignment organic SEI. We find that soluble...

Silicon monoxide is a promising alternative anode material due to its much higher capacity than graphite, and improved cyclability over other Si anodes. An in-depth analysis of the lithium silicide (Li xSi) phases that form during lithiation/delithiation SiO presented here results are compared with pure-Si A series materials first prepared by heating amorphous silicon (a-SiO) at different temperatures, X-ray diffraction 29Si NMR revealing they comprise small domains surrounded SiO2, domain...

Telechelic oligo- and poly(dimethylsiloxanes) 1 2, with two ureidopyrimidone (UPy) functional groups, have been prepared via a hydrosilylation reaction. The compounds characterized in solution by 1H NMR viscometry the solid state 13C NMR, FTIR, rheology measurements. measurements show that UPy groups of 2 are associated quadruple hydrogen bonds donor−donor−acceptor−acceptor (DDAA) array. In many aspects, materials behave like entangled, high molecular weight polymers. Compound has Tg at −119...

Immobilization of EPDM chains on the surface carbon black and network structure in rubber matrix filled rubbers were studied by low-field proton NMR experiments. Advanced experiments unambiguously show strong immobilization chain fragments black. The thickness immobilized EPDM–carbon interfacial layer is estimated to be ≥0.6 nm. average number monomer units per adsorption site approximately nine, which suggests preferential at crystal boundaries carbon-black particles. adsorbed form physical...

Lewis acid Snβ-type zeolites with varying amounts of Brønsted Al in the framework were synthesized using a simple two-step procedure comprising partial dealumination β zeolite under action acid, followed by grafting SnCl4·5H2O dry isopropanol. Characterization thus-prepared Al-containing Snβ (Sn/pDeAlβ) ICP, (pyridine probed) FTIR, and 27Al MAS NMR demonstrates presence AlIII. Tetrahedral acidic SnIV is present, as ascertained combination techniques such EPMA, 119Sn Möβbauer, XPS, UV–vis. A...

Although monodisperse amorphous silica nanoparticles have been widely investigated, their formation mechanism is still a topic of debate. Here, we demonstrate the from colloidally stabilized primary particles, which at critical concentration undergo concerted association process, concomitant with morphological and structural collapse. The formed assemblies grow further by addition particles onto surface. presented mechanism, consistent previously reported observations, reconciles different...

The dual template synthesis of zeolite SSZ-13 by use trimethyl-adamantanammonium hydroxide and a diquaternary-ammonium mesoporogen induces considerable mesoporosity without impeding microporosity. strongly improved accessibility Brønsted sites in mesoporous increases its stability during application as an acid catalyst the methanol-to-olefins reaction.

MgH 2 is a promising material for reversible solid‐state hydrogen storage. It known that particle size can have strong impact on dynamics and sorption characteristics, but more detailed insight has been hampered by the great challenge to prepare small well‐defined particles study their storage properties upon cycling. The preparation of nanoparticles supported high surface area carbon aerogels with pore sizes varying from 6–20 nm reported. Two distinctly different populations are observed:...

Abstract A series of faujasite zeolites was modified by extraframework Al (Al EF ) with the goal to investigate influence such species on intrinsic Brønsted acidity and catalytic activity towards paraffin cracking. The chemical state zeolite were investigated 27 MAS NMR CO ads IR spectroscopy, H/D exchange reaction, propane Strongly acidic defect‐free Y obtained substitution framework Si (NH 4 2 SiF 6 . In accordance next‐nearest‐neighbor model, protons increased decreasing density. This...

The parasitic reactions associated with reduced oxygen species and the difficulty in achieving high theoretical capacity have been major issues plaguing development of practical nonaqueous Li-O2 batteries. We hereby address above by exploring synergistic effect 2,5-di-tert-butyl-1,4-benzoquinone H2O on chemistry a battery. Water stabilizes quinone monoanion dianion, shifting reduction potentials to more positive values (vs Li/Li+). When water are used together (largely) battery, cell...

Hollow mesoporous silica spheres that are highly defined in shape and size (see Figure) prepared using a poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) [PEO–PPO–PEO] block copolymer based emulsion as the template, sodium silicate source. The wall structure of particles depends on reaction temperature can be monitored small‐angle X‐ray scattering, solid‐state NMR spectroscopy, cryo‐transmission electron microscopy.

Herein we report the synthesis and characterization of hollow silica spheres with a narrow size distribution, uniform wall thickness, worm-like pore structure. The formation these was monitored by confocal laser scanning microscopy dynamic light scattering. A model for molecular build-up is derived from data in combination studies as-made particles transmission electron microscopy, analysis, thermogravimetric solid-state nuclear magnetic resonance. We further demonstrate that can be used...

Rounding up the POSSe: Polyhedral oligomeric silsesquioxanes (POSS), one of smallest hybrid nano building blocks, were weaved into multifunctional hierarchical mesoporous materials. The organic–inorganic material was synthesized by coassembly and condensation POSS compound around block copolymer P123 micelles subsequent release porogen (see scheme), resulting in a uniform pore size 4.40 nm. Supporting information for this article is available on WWW under...

The hydrogen-bonded hexagonal columnar LC (Colhd) phases formed by benzene-1,3,5-tricarboxamide (BTA) derivatives can be aligned uniformly an electric field and display switching behavior with a high remnant polarization. polar in three symmetrically substituted BTAs alkyl chains varying length between 6 18 carbon atoms (C6, C10, C18) was investigated electro-optical experiments, dielectric relaxation spectroscopy (DRS), solid-state NMR. goal to characterize ferroelectric properties of...