Structural Designs for Accommodating Volume Expansion in Sodium Ion Batteries

At the forefront of energy storage field, developing sodium ion batteries (SIBs) has drew a wide concern due to relatively low cost and abundant resource, comparing with lithium ion batteries (LIBs). Serious volume expansion constraints the electrochemical performance of the conversion/alloying materials, despite of their high reversible capacities or theoretical capacities. Here, from the perspective of structural designs, we systematically study four types of routes to accommodate volume expansion. Delicate and peculiar nanostructures based on nanocrystallization engineering are widely focused on, covering nanosheet assembly and nanoarray construction. Robust materials such as carbon‐based materials can be utilized as the buffer matrix, mitigating the mechanical stress during the charge/discharge process. Besides, recent studies have demonstrated void space reservation in nanostructures was also beneficial for adapting to volume changes. Moreover, for conversion materials, numerous works have confirmed the advantageous influence of interlayer spacing regulation. We also explained the superiority and challenges for further giving scope to structural designs. Sketching out the future studies in SIBs, in situ characterizations are supposed to be highlighted, as well as in‐depth researches on the stress evolution caused by volume expansion.     

A method for the analysis of sucralose with electrospray LC/MS in recipient waters and in sewage effluent subjected to tertiary treatment technologies

A method for the analysis of the artificial sweetener sucralose in sewage water and recipient water was developed. Extraction and clean up was performed with solid-phase extraction utilising Oasis HLB columns. Detection was made by liquid chromatography electrospray mass spectrometry (LC/MS). The triple-quadrupole mass spectrometer was operated in multiple reaction monitoring (MRM) mode. However, ‘pseudo MRM’ was used, a technique where the two quadrupoles monitor the same m/z. The sodium adduct of sucralose was used for quantification, since lower detection limits were obtained as compared to the sucralose quasi-molecular ion in negative ion mode. The two ions with highest intensity in the chlorine isotope pattern were monitored. The reduction of matrix effects with this approach is discussed. The method limit of quantification (MLOQ) for sewage water was 0.2?µg?L^?1, whereas for recipient water MLOQ was 0.02?µg?L^?1. The method was used to analyse effluent samples from an experimental sewage treatment plant (STP) to assess the efficiency of tertiary treatment techniques for removal of sucralose. Filtration through activated carbon was shown to be efficient, while ozonation, advanced oxidation techniques and membrane bioreactors were less efficient. Analyses of receiving waters showed low dilution of sucralose emitted from the STPs.     

The influence of using sodium dithionite as SARA agent in miniemulsion ATRP

The supplemental activator and reducing agent atom transfer radical polymerization (SARA ATRP) of butyl acrylate (nBA) and styrene (Sty) using miniemulsion is reported for the first time. The polymerization was carried out in the presence of Cu(II)Br₂‐based catalytic systems using EHA₆TREN or BPMODA* and sodium dithionite (Na₂S₂O₄) as SARA agent. Kinetic data revealed a controlled polymerization for both monomers, with a very stringent control over the molecular weight distribution (Ð ≤ 1.2) but low monomer conversion. Reaction conditions were optimized in an attempt to understand the kinetics of polymerization, aiming to increase the final monomer conversion while maintaining the control over the polymerization. Self‐chain extension reactions revealed low chain end fidelity, which corroborate the impossibility of increasing monomer conversion even after the judicious variation of the main polymerization parameters (monomers, surfactant, deactivator, and Na₂S₂O₄ concentrations, and its method of addition). The data presented suggest a particular feature of Na₂S₂O₄ in these polymerization systems involving the significant formation of dead chains ends, which has never been observed for any other reported system using this SARA agent. In contrast, control ARGET miniemulsion experiments under the same reaction conditions and using ascorbic acid as reducing agent allowed to achieve high monomer conversions. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 879–888     

水性黏结剂海藻酸钠和果胶酸钠对锂离子电池石墨负极电化学性能的影响

利用循环伏安和恒电流充放电测试,结合扫描电镜观测,研究了水性黏结剂海藻酸钠和果胶酸钠对石墨负极电化学性能的影响.结果表明,石墨负极在这两种黏结剂中均可以进行有效的嵌锂脱锂循环,且电化学循环性能较好,50次循环后可逆比容量损失不超过5%.两种水性黏结剂在改善石墨电极的嵌脱锂循环性能方面具有较好的发展前景.     

WS2 Nanowires as a High‐Performance Anode for Sodium‐Ion Batteries

We report the synthesis and anode application for sodium‐ion batteries (SIBs) of WS₂ nanowires (WS₂ NWs). WS₂ NWs with very thin diameter of ≈25 nm and expanded interlayer spacing of 0.83 nm were prepared by using a facile solvothermal method followed by a heat treatment. The as‐prepared WS₂ NWs were evaluated as anode materials of SIBs in two potential windows of 0.01–2.5 V and 0.5–3 V. WS₂ NWs displayed a remarkable capacity (605.3 mA h g^?1 at 100 mA g^?1) but with irreversible conversion reaction in the potential window of 0.01–2.5 V. In comparison, WS₂ NWs showed a reversible intercalation mechanism in the potential window of 0.5–3 V, in which the nanowire‐framework is well maintained. In the latter case, the interlayers of WS₂ are gradually expanded and exfoliated during repeated charge–discharge cycling. This not only provides more active sites and open channels for the intercalation of Na⁺ but also facilitates the electronic and ionic diffusion. Therefore, WS₂ NWs exhibited an ultra‐long cycle life with high capacity and rate capability in the potential window of 0.5–3 V. This study shows that WS₂ NWs are promising as the anode materials of room‐temperature SIBs.     

Novel oxidative aromatic alkene cleavage with sodium nitrite under mild conditions

We have developed a simple and practical process for the oxidation of aromatic alkene to the corresponding carbonyl compounds using NaNO₂ as an oxidant. The practical utility of this oxidative process has been demonstrated in the gram-scale oxidation of 1-(tert-butyl)-4-vinylbenzene.     

3,5,6-三氯吡啶-2-醇钠的合成研究进展

综述了3,5,6-三氯吡啶-2-醇钠的合成方法,并比较了各种路线的利弊,重点介绍了三氯乙酰氯路线的合成方法.提出三氯乙酰氯路线的一步合成法具有更好的经济效益,适合国内大规模生产.     

Sodium dodecyl sulfate sensitized electrochemical method for sub-picomole level determination of topotecan hydrochloride at a novel disposable electrode

A sub-picomole level topotecan hydrochloride determination method was first proposed using sodium dodecyl sulfate (SDS) as a sensitized reagent at a novel disposable electrode (an improved wax-impregnated graphite electrode).The effects of different kinds of surfactants on the electrochemical response to topotecan hydrochloride were examined.The results indicate the electrochemical signal was apparently improved by SDS.At optimal conditions,the oxidative peak current increased linearly with the logarithm of...     

The 24Na Induced Activity as a Neutron Dosimeter for Radiobiologial Experiments

Measurement of the ²⁴Na induced activity as a part of a dosimetric system for radiobiological experiments was found to be an approach characterized by its proper reliability, reproducibility (relative error less than 8-5%) and high sensitivity (activities of about 0-01 μCi may be detected).