Engineering of Aromatic Naphthalene and Solvent Molecules to Optimize Chemical Prelithiation for Lithium‐Ion Batteries

A cost-effective chemical prelithiation solution, which consists of Li$^+$, polyaromatic hydrocarbon (PAH), and solvent, is developed for a model hard carbon (HC) electrode. Naphthalene and methyl-substituted naphthalene PAHs, namely 2-methylnaphthalene and 1-methylnaphthalene, are first compared. Grafting an electron-donating methyl group onto the benzene ring can decrease electron affinity and thus reduce the redox potential, which is validated by density functional theory calculations. Ethylene glycol dimethyl ether (G1), diethylene glycol dimethyl ether, and triethylene glycol dimethyl ether solvents are then compared. The G1 solution has the highest conductivity and least steric hindrance, and thus the 1-methylnaphthalene/G1 solution shows superior prelithiation capability. In addition, the effects of the interaction time between Li$^+$ and 1-methylnaphthalene in G1 solvent on the electrochemical properties of a prelithiated HC electrode are investigated. Nuclear magnetic resonance data confirm that 10-h aging is needed to achieve a stable solution coordination state and thus optimal prelithiation efficacy. It is also found that appropriate prelithiation creates a more Li$^+$-conducing and robust solid-electrolyte interphase, improving the rate capability and cycling stability of the HC electrode

Physicochemical Properties of Glycine-Based Ionic Liquid [QuatGly-OEt][EtOSO3] (2-Ethoxy-1-ethyl-1,1-dimethyl-2-oxoethanaminium ethyl sulfate) and Its Binary Mixtures with Poly(ethylene glycol) (Mw = 200) at Various Temperatures

This work includes specific basic characterization of synthesized glycine-based Ionic Liquid (IL) [QuatGly-OEt][EtOSO3] by NMR, elementary analysis and water content. Thermophysical properties such as density, ρ, viscosity, η, refractive index, n, and conductivity, κ, for the binary mixture of [QuatGly-OEt][EtOSO3] with poly(ethylene glycol) (PEG) [Mw = 200] are measured over the whole composition range. The temperature dependence of density and dynamic viscosity for neat [QuatGly-OEt][EtOSO3] and its binary mixture can be described by an empirical polynomial equation and by the Vogel-Tammann-Fucher (VTF) equation, respectively. The thermal expansion coefficient of the ILs is ascertained using the experimental density results, and the excess volume expansivity is evaluated. The negative values of excess molar volume for the mixture indicate the ion-dipole interactions and packing between IL and PEG oligomer. The results of binary excess property (VmE ) and deviations (Δη, Δxn, ΔΨn, ΔxR, and ΔΨR) are discussed in terms of molecular interactions and molecular structures in the binary mixture

Synthesis, Characterization and Photovoltaic Properties of Di-Anchoring Organic Dyes

Three new organic dyes comprising carbazole, iminodibenzyl and phenothiazine moieties, as electron donors and di-anchoring rhodanine rings as the electron acceptors, were synthesized and evaluated for use in dye-sensitized solar cells. A solar cell employing dye-containing phenothiazine as a hole-transporting unit and di-anchoring rhodanine rings as the electron acceptors exhibits a short circuit photocurrent density of 10.6 mA cm-2, an open-circuit voltage of 0.658 V and a fill factor of 0.7, corresponding to an overall conversion efficiency of 4.91% at standard AM 1.5 sunlight

Functional characterization of cellulases identified from the cow rumen fungus Neocallimastix patriciarum W5 by transcriptomic and secretomic analyses

<p>Abstract</p> <p>Background</p> <p><it>Neocallimastix patriciarum</it> is one of the common anaerobic fungi in the digestive tracts of ruminants that can actively digest cellulosic materials, and its cellulases have great potential for hydrolyzing cellulosic feedstocks. Due to the difficulty in culture and lack of a genome database, it is not easy to gain a global understanding of the glycosyl hydrolases (<it>GHs</it>) produced by this anaerobic fungus.</p> <p>Results</p> <p>We have developed an efficient platform that uses a combination of transcriptomic and proteomic approaches to <it>N. patriciarum </it>to accelerate gene identification, enzyme classification and application in rice straw degradation. By conducting complementary studies of transcriptome (Roche 454 GS and Illumina GA IIx) and secretome (ESI-Trap LC-MS/MS), we identified 219 putative <it>GH </it>contigs and classified them into 25 <it>GH</it> families. The secretome analysis identified four major enzymes involved in rice straw degradation: β-glucosidase, endo-1,4-β-xylanase, xylanase B and Cel48A exoglucanase. From the sequences of assembled contigs, we cloned 19 putative cellulase genes, including the <it>GH1</it>, <it>GH3</it>, <it>GH5</it>, <it>GH6</it>, <it>GH9</it>, <it>GH18</it>, <it>GH43 </it>and <it>GH48 </it>gene families, which were highly expressed in <it>N. patriciarum </it>cultures grown on different feedstocks.</p> <p>Conclusions</p> <p>These <it>GH </it>genes were expressed in Pichia pastoris and/or Saccharomyces cerevisiae for functional characterization. At least five novel cellulases displayed cellulytic activity for glucose production. One β-glucosidase (W5-16143) and one exocellulase (W5-CAT26) showed strong activities and could potentially be developed into commercial enzymes.</p

Synthesis and Characterization of Organic Dyes Containing Various Donors and Acceptors

New organic dyes comprising carbazole, iminodibenzyl, or phenothiazine moieties, respectively, as the electron donors, and cyanoacetic acid or acrylic acid moieties as the electron acceptors/anchoring groups were synthesized and characterized. The influence of heteroatoms on carbazole, iminodibenzyl and phenothiazine donors, and cyano-substitution on the acid acceptor is evidenced by spectral, electrochemical, photovoltaic experiments, and density functional theory calculations. The phenothiazine dyes show solar-energy-to-electricity conversion efficiency (η) of 3.46–5.53%, whereas carbazole and iminodibenzyl dyes show η of 2.43% and 3.49%, respectively

Copolymers Based on Indole-6-Carboxylic Acid and 3,4-Ethylenedioxythiophene as Platinum Catalyst Support for Methanol Oxidation

Indole-6-carboxylic acid (ICA) and 3,4-ethylenedioxythiophene (EDOT) are copolymerized electrochemically on a stainless steel (SS) electrode to obtain poly(indole-6-carboxylic acid-co-3,4-ethylenedioxythiophene)s (P(ICA-co-EDOT))s. The morphology of P(ICA-co-EDOT)s is checked using scanning electron microscopy (SEM), and the SEM images reveal that these films are composed of highly porous fibers when the feed molar ratio of ICA/EDOT is greater than 3/2. Platinum particles can be electrochemically deposited into the P(ICA-co-EDOT)s and PICA films to obtain P(ICA-co-EDOT)s-Pt and PICA-Pt composite electrodes, respectively. These composite electrodes are further characterized using X-ray photoelectron spectroscopy (XPS), SEM, X-ray diffraction analysis (XRD), and cyclic voltammetry (CV). The SEM result indicates that Pt particles disperse more uniformly into the highly porous P(ICA3-co-EDOT2) fibers (feed molar ratio of ICA/EDOT = 3/2). The P(ICA3-co-EDOT2)-Pt nanocomposite electrode exhibited excellent catalytic activity for the electrooxidation of methanol in these electrodes, which reveals that P(ICA3-co-EDOT2)-Pt nanocomposite electrodes are more promising for application in an electrocatalyst as a support material

Applications of Tris(4-(thiophen-2-yl)phenyl)amine- and Dithienylpyrrole-based Conjugated Copolymers in High-Contrast Electrochromic Devices

Tris(4-(thiophen-2-yl)phenyl)amine- and dithienylpyrrole-based copolymers (P(TTPA-co-DIT) and P(TTPA-co-BDTA)) were electropolymerized on ITO electrode by applying constant potentials of 1.0, 1.1, and 1.2 V. Spectroelectrochemical investigations revealed that P(TTPA-co-DIT) film displayed more color changes than P(TTPA-co-BDTA) film. The P(TTPA-co-DIT) film is yellow in the neutral state, yellowish-green and green in the intermediate state, and blue (1.2 V) in highly oxidized state. The ∆Tmax of the P(TTPA-co-DIT) and P(TTPA-co-BDTA) films were measured as 60.3% at 1042 nm and 47.1% at 1096 nm, respectively, and the maximum coloration efficiency (η) of P(TTPA-co-DIT) and P(TTPA-co-BDTA) films were calculated to be 181.9 cm2·C−1 at 1042 nm and 217.8 cm2·C−1 at 1096 nm, respectively, in an ionic liquid solution. Dual type electrochromic devices (ECDs) consisting of P(TTPA-co-DIT) (or P(TTPA-co-BDTA)) anodic copolymer, ionic liquid-based electrolyte, and poly(3,4-(2,2-diethylpropylenedioxy)thiophene) (PProDOT-Et2) cathodic polymer were constructed. P(TTPA-co-BDTA)/PProDOT-Et2 ECD showed high ΔTmax (48.1%) and high coloration efficiency (649.4 cm2·C−1) at 588 nm. Moreover, P(TTPA-co-DIT)/PProDOT-Et2 and P(TTPA-co-BDTA)/PProDOT-Et2 ECDs displayed satisfactory optical memory and long term switching stability

Three Carbazole-Based Polymers as Potential Anodically Coloring Materials for High-Contrast Electrochromic Devices

Three carbazole-based conjugated polymers (poly(3,6-di(2-thienyl)carbazole) (PDTC), poly(2,7-bis(carbazol-9-yl)-9,9-spirobifluorene) (PS2CBP), and poly(3,6-bis(N-carbazole)-N-ethylcarbazole) (PCEC)) are synthesized using electrochemical polymerization. The spectroelectrochemical studies indicate that the PDTC, PS2CBP, and PCEC films show reversible electrochromic behaviors in their redox states, and the PS2CBP film shows a distinct color transition with four various colors (gray at 0 V, grayish-green at 1.0 V, moss green at 1.2 V, and foliage green at 1.4 V). The maximum optical contrast of the PS2CBP and PCEC films is 39.83% at 428 nm and 32.41% at 420 nm, respectively, in an ionic liquid solution. Dual-type electrochromic devices (ECDs) that employ PDTC, PS2CBP, or PCEC film as an anodic layer, and PProDOT-Et2 film as a cathodic layer, were constructed. The as-prepared PCEC/PProDOT-Et2 ECD shows high optical contrast (38.25% at 586 nm) and high coloration efficiency (369.85 cm2 C−1 at 586 nm), and the PS2CBP/PProDOT-Et2 ECD shows high optical contrast (34.45% at 590 nm), good optical memory, and good long-term cycling stability

Applications of Three Dithienylpyrroles-Based Electrochromic Polymers in High-Contrast Electrochromic Devices

Three dithienylpyrroles (1-(4-(methylthio)phenyl)-2,5-di(thiophen-2-yl)-pyrrole (MPS), 1-(4-methoxyphenyl)-2,5-di(thiophen-2-yl)-pyrrole (MPO), and 4-(2,5-di(thiophen-2-yl)-pyrrol-1-yl)benzonitrile (ANIL)) were synthesized and their corresponding polydithienylpyrroles (PSNS) were electrosynthesized using electrochemical polymerization. Spectroelectrochemical studies indicated that poly(1-(4-(methylthio)phenyl)-2,5-di(thiophen-2-yl)-pyrrole) (PMPS) film was green, dark green, and brown in the neutral, oxidation, and highly oxidized state, respectively. The incorporation of a MPS unit into the PSNS backbone gave rise to a darker color than those of the MPO and ANIL units in the highly oxidized state. The PMPS film showed higher ΔTmax (54.47% at 940 nm) than those of the PMPO (43.87% at 890 nm) and PANIL (44.63% at 950 nm) films in an ionic liquid solution. Electrochromic devices (ECDs) employing PMPS, PMPO, and PANIL as anodic layers and poly(3,4-(2,2-diethypropylenedioxy)thiophene)(PProDOT-Et2) as a cathodic layer were constructed. PMPO/PProDOT-Et2 ECD showed the highest ΔTmax (41.13%) and coloration efficiency (674.67 cm2·C−1) at 626 nm, whereas PMPS/PProDOT-Et2 ECD displayed satisfactory ΔTmax (32.51%) and coloration efficiency (637.25 cm2·C−1) at 590 nm. Repeated cyclic voltammograms of PMPS/PProDOT-Et2, PMPO/PProDOT-Et2, and PANIL/PProDOT-Et2 ECDs indicated that ECDs had satisfactory redox stability

Crystallization Behaviors of Composites Comprising Biodegradable Polyester and Functional Nucleation Agent

In this study, a thorough study of the crystallization behaviors of the biodegradable polymer composites of poly(ethylene succinate) (PESu) and hexagonal boron nitride (h-BN) was carried out. We found that h-BN had a significant nucleation effect on crystallization behaviors. DSC isothermal crystallization results demonstrated that the crystallization time of the PESu/h-BN composites became shorter after adding h-BN. The rate constant k values calculated from the Avrami equation were larger for the composites, demonstrating that PESu’s crystallization rate was increased by adding h-BN. TEM and SEM images showed the well-dispersed h-BN in the PESu matrix. Optical microscopy revealed that the PESu/h-BN composites formed more and smaller spherulites than neat PESu did, which confirmed that h-BN caused the nucleation effect. H-BN also accelerated non-isothermal crystallization kinetics. We discussed the behaviors of the Mo model, which demonstrated that h-BN promoted the kinetics of non-isothermal crystallization. The XRD diffraction patterns showed that h-BN in the composites would not obviously change the crystalline structure of PESu