In-situ synthesis of interconnected SWCNT/OMC framework on silicon nanoparticles for high performance lithium-ion batteries

AbstractIn spite of silicon has a superior theoretical capacity, the large volume expansion of Si anodes during Li+ insertion/extraction is the bottle neck that results in fast capacity fading and poor cycling performance. In this paper, we report a silicon, single-walled carbon nanotube, and ordered mesoporous carbon nanocomposite synthesized by an evaporation-induced self-assembly process, in which silicon nanoparticles and single-walled carbon nanotubes were added into the phenolic resol with F-127 for co-condensation. The ordered mesoporous carbon matrix and single-walled carbon nanotubes network could effectively accommodate the volume change of silicon nanoparticles, and the ordered mesoporous structure could also provide efficient channels for the fast transport of Li-ions. As a consequence, this hybrid material exhibits a reversible capacity of 861 mAh g−1 after 150 cycles at a current density of 400 mA g−1. It achieves significant improvement in the electrochemical performance when compared with the raw materials and Si nanoparticle anodes

Optimization and Evaluation of Alkali-Pretreated Paeonia Ostii Seed Coats as Adsorbent for the Removal of Mb From Aqueous Solution

A novel effi cient adsorbent, alkali-pretreated Paeonia ostii seed coats (AP-PSC), was investigated for the removal of methylene blue (MB) dye from solution. Orthogonal array design was applied to optimize the process parameters viz. alkali concentration, liquid-solid ratio (LSR) and pretreatment time. The results revealed that the optimal pretreatment conditions were at 0.8% (w/w) NaOH with LSR of 0.35 L g-1 treating for 50 min. Equilibrium and kinetic studies indicated that Langmuir isotherm and Pseudo-second-order models described the experimental data well. The maximum adsorption capability was of 368.2 mg g-1 for MB at 25oC. Thermodynamic parameters suggested that the AP-PSC adsorption process was physical, endothermic and spontaneous. Furthermore, the adsorption process was infl uenced by several interactive mechanisms, including ion-exchange, as well as Van der Waals forces and hydrogen bonds that occur concomitantly. It was concluded that AP-PSC may be potential as an effi cient adsorbent to remove MB from solution

Study on ionic liquids based novel method for separation and purification of silkworm pupa protein

Silkworm pupa protein (SPP) that obtained by traditional method usually had a high fat content, which would impose restrictions on the further use of SPP. Herein, various functionalized ionic liquids (ILs) were used to extract SPP from silkworm pupae, the structure-performance relationship of ILs with their SPP separation performance were explored at the same time. The research showed that the maxi-mum extraction yield of SPP was up to 62.6% with less than 0.5% low fat content by using 1-ethyl-3-methylimidazolium chloride ([Emim]Cl), when the dissolution experiment was conducted at 90 ? for 24 h with ethanol bath as the regeneration solvent. Comparing with the structure of raw material, the regenerated SPP maintained the native protein backbone. Meanwhile, all regenerated SPP showed a de-creased crystallinity, which also exhibited decreased fraction of the alpha-helix comparing to that beta-sheet united with coil random structures. (C) 2022 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences

Adamantane-Based Cation and [MFn](-) Anion Synergistically Enhanced Catalytic Performance of Sulfuric Acid for Isobutane Alkylation

A series of adamantane-based ionic liquids (ADM-ILs) with [MFn](-) anions were synthesized as cocatalysts for the alkylation of isobutane and butene. By systematically tuning the structures of the cation and anion and their combination, we obtained the optimized ionic liquid, ADM-C-12-SbF6, which exhibited significant enhancements in the C-8 selectivities [especially to trimethylpentanes (TMPs)], the research octane number (RON) of the alkylate products, and the lifetime of sulfuric acid. The selectivity to TMPs was improved from 81.9% to 84.5%, and the alkylate RON was improved from 96.6 to 98.6 upon the addition of the ADM-ILs. In addition, the lifetimes of the ADM-IL/H2SO4 systems were increased to twice that of H2SO4 alone. Based on experimental measurements and DFT calculations, all of these enhancements were attributed to the multifunctions cooperatively integrated into the task-specific ADM-ILs, such as surfactant action, improving the interfacial properties of the acid/hydrocarbon biphases; buffer action, stabilizing the acidity changes during the reaction process; and hydride donor action, increasing the H- transfer rate, which promoted the production of TMPs. This study is beneficial for improving the isobutane alkylation process catalyzed by concentrated sulfuric acid.</p

Study on ionic liquids based novel method for separation and purification of silkworm pupa protein

Silkworm pupa protein (SPP) that obtained by traditional method usually had a high fat content, which would impose restrictions on the further use of SPP. Herein, various functionalized ionic liquids (ILs) were used to extract SPP from silkworm pupae, the structure-performance relationship of ILs with their SPP separation performance were explored at the same time. The research showed that the maxi-mum extraction yield of SPP was up to 62.6% with less than 0.5% low fat content by using 1-ethyl-3-methylimidazolium chloride ([Emim]Cl), when the dissolution experiment was conducted at 90 ? for 24 h with ethanol bath as the regeneration solvent. Comparing with the structure of raw material, the regenerated SPP maintained the native protein backbone. Meanwhile, all regenerated SPP showed a de-creased crystallinity, which also exhibited decreased fraction of the alpha-helix comparing to that beta-sheet united with coil random structures. (C) 2022 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences

Synthesize of silicon/carbon nanosheets with NaCl template and its application as anode material of lithium-ion batteries

Lithium-ion batteries (LIBs) are used extensively in various applications such as mobile phones and portable computer. Silicon (Si) is regarded as a kind of promising anode material in LIBs because of its high theoretical capacity and low working potential. The major challenges related to Si anodes are their huge volume changes and poor conductivity during lithiation-delithiation. Herein, a two-dimensional structure of Si/petroleum pitches based carbon nanosheets (Si/CNSs) was successfully synthesized via a green and recyclable NaCl template method. This peculiar structural feature of Si/CNS can effectively accommodate the volume expansion of Si anodes and improve their electrochemical performance. A typical sample of Si/CNS-2 exhibits a high reversible capacities of 901mAhg(-1) at 100mAg(-1), good cycling stability (capacity retention of 655mAhg(-1) after 100 cycles at 300mAg(-1)) and excellent rate capability (533mAhg(-1) at 2Ag(-1)). This approach is simple and environment-friendly, which may supply a practicality way to prepare Si-based anode materials for high-performance LIBs

Multi-objective optimization of biomass to biomethane system

The superstructure optimization of biomass to biomethane system through digestion is conducted in this work. The system encompasses biofeedstock collection and transportation, anaerobic digestion, biogas upgrading, and digestate recycling. We propose a multicriteria mixed integer nonlinear programming (MINLP) model that seeks to minimize the energy consumption and maximize the green degree and the biomethane production constrained by technology selection, mass balance, energy balance, and environmental impact. A multi-objective MINLP model is proposed and solved with a fast nondominated sorting genetic algorithm II (NSGA-II). The resulting Pareto-optimal surface reveals the trade-off among the conflicting objectives. The optimal results indicate quantitatively that higher green degree and biomethane production objectives can be obtained at the expense of destroying the performance of the energy consumption objective. Keywords: Multiobjective optimization, Biomass to biomethane system, Green degree, Mixed-integer nonlinear programmin

Conversion of bis(2-hydroxyethylene terephthalate) into 1,4-cyclohexanedimethanol by selective hydrogenation using RuPtSn/Al2O3

1,4-Cyclohexanedimethanol (CHDM) is a highly valued and widely used monomer in the polymer industry. Bis(2-hydroxyethylene terephthalate) (BHET), the product of glycolysis of waste PET, is an excellent raw material for the preparation of CHDM. Herein, a series of monometallic, bimetallic and trimetallic supported catalysts were prepared for the one-pot conversion of BHET into CHDM by the impregnation method and good performance was found over trimetallic RuPtSn/Al2O3 catalysts containing various active sites to catalyze the hydrogenation of the phenyl and carbonyl groups. The influences of various reaction parameters including temperature, pressure and time on the hydrogenation reaction were studied, and 100% conversion and 87.1% yield of CHDM were obtained with the trimetallic supported catalyst with Ru/Sn 1.5. Moreover, through the comparison between various methods for the preparation of CHDM, the conversion of BHET into CHDM by the one-pot method is considered one of the most competitive methods

NH4F and carbon nanotubes co-modified LiNi0.88Co0.09Al0.03O2 cathode material with enhanced electrochemical properties for Li-ion batteries

LiNi0.88Co0.09Al0.03O2 cathode material was modified with NH4F and carbon nanotubes through high temperature solid phase reaction and a superficial deposit process. The results of X-ray diffraction demonstrate that the interslab distances was enlarged after fluorine doping, which is more conductive to the internal diffusion of lithium ions. The X-ray photoelectron spectroscopy confirms the changes of valence states of the metallic elements after F- doping. The Scanning electron microscope and the transmission electron microscopy results demonstrate that the carbon nanotubes coating layer was successfully loaded on the surface of the material. The rate capability and the cycle stability of the composite materials were improved remarkably. Eventually, the modified cathode material exhibits a reversible capacity up to 194.3mAhg(-1) at 0.1C, corresponding to 88% capacity retention after 150 cycles at 2C between 2.8 and 4.3V