Controlling Reversible Expansion of Li2O2 Formation and Decomposition by Modifying Electrolyte in Li-O2 Batteries

锂空电池分别使用空气中的氧气和金属锂作为正负极活性材料，具有极高的能量密度。但是，这一体系尚不能实现商业化的应用，其中一些关键问题未能解决。由于其正极活性材料是气体，使得电化学反应涉及气-液-固三相界面，电极过程十分复杂。与其它二次电池相比，空气电极需要考虑结构因素和催化因素。不仅要改善氧气电化学反应的动力学迟缓问题，还要考虑放电产物的驻留空间问题。董全峰教授课题组在前期开展了基于空气电极固相表面电催化研究，并结合电极结构方面的问题，构筑了有利于氧气发生反应的仿生开放式结构电极。 该研究工作主要由化学化工学院2015级iChEM直博生林晓东（第一作者）在董全峰教授、郑明森副教授和龚磊副教授的共同指导下完成，理论计算由袁汝明助理教授（共同第一作者）完成，曹勇、丁晓兵、蔡森荣、韩博闻等学生参与了部分工作。周志有教授和洪宇浩博士生在电化学微分质谱方面给予大力的帮助与支持。【Abstract】The aprotic lithium-oxygen (Li-O2) battery has attracted worldwide attention because of its ultrahigh theoretical energy density. However, its practical application is critically hindered by cathode passivation, large polarization, and severe parasitic reactions. Here, we demonstrate an originally designed Ru(Ⅱ) polypyridyl complex (RuPC) though which the reversible expansion of Li2O2 formation and decomposition can be achieved in Li-O2 batteries. Experimental and theoretical results revealed that the RuPC can not only expand the formation of Li2O2 in electrolyte but also suppress the reactivity of LiO2 intermediate during discharge, thus alleviating the cathode passivation and parasitic reactions significantly. In addition, an initial delithiation pathway can be achieved when charging in turn; thus, the Li2O2 products can be decomposed reversibly with a low overpotential. Consequently, the RuPC-catalyzed Li-O2 batteries exhibited a high discharge capacity, a low charge overpotential, and an ultralong cycle life. This work provides an alternative way of designing the soluble organic catalysts for metal-O2 batteries.This work was supported by the National 973 Program (2015CB251102), the Key Project of National Natural Science Foundation of China (21673196, 21621091, 21703186, 21773192),and the Fundamental Research Funds for the Central Universities (20720150042,20720150043). The authors thank Prof. Eric Meggers at Philipps-Univeristaet Marburg for his discussion about the synthesis of RuPC complex; Prof. Gang Fu at Xiamen University for his instructive discussions in DFT calculations; Lajia Yu and Dandan Tao at Xiamen University for their assistance in EPR experiments and UV-Vis spectroscopy experiments, respectively; and Yu Gu and Tao Wang at Xiamen University for their discussions in XPS results and CV data,respectively. 该工作得到科技部重大基础研究计划（项目批准号：2015CB251102）、国家自然科学基金（项目批准号：21673196、21621091、21703186、21773192）和中央高校基本科研业务费专项资金（项目批准号：20720150042、20720150043）的资助。 此外，感谢傅钢教授在理论计算方面的讨论和建议，Eric Meggers教授在配合物合成上的讨论，泉州师范学院吴启辉教授和化学化工学院谷宇博士生在X射线光电子能谱方面的帮助，于腊佳老师在电子顺磁共振实验上的帮助，陶丹丹博士生在紫外可见光谱测试上的帮助以及王韬博士生在循环伏安方面的讨论

Synthesis of MeO-PEG-Supported Ferrocenyloxazoline Ligands and Their Application in Asymmetric Catalysis.

Synthesis of MeO-PEG-Supported Ferrocenyloxazoline Ligands and Their Application in Asymmetric Catalysis

Recent Advances in Big Defensins of Marine Invertebrates

Big defensins are cysteine-rich cationic antimicrobial peptides(AMPs)formed by serially connecting the N-terminal hydrophobic domain with the C-terminal beta-defensin-like domain.These domains have different antibacterial activities.Moreover,big defensins have conserved salt-stable antimicrobial activity and the N-terminal domain can drive the self-assembly of big defensins into nanonetworks that entrap and kill bacteria.So far,big defensins have been mainly found in the innate immune system of invertebrate animals and amphioxus that is a primitive chordate holding a key phylogenetic position bridging from invertebrates to vertebrates.Moreover,the C-terminal domain of big defensins has similar structure and bioactivity to the beta-defensin of vertebrates,which has aroused interest in investigating the biological evolution and function of defensins and the evolution of the immune system in species related to defensins.Based on the progress that has been made in the identification and characterization of big defensins in recent years,herein we present an integrated review of the molecular structures and evolution of big defensins,together with their antibacterial mechanism and expression regulation as well as their application prospects in the fields of aquaculture and aquatic product safety and in the development of new antimicrobial drugs.This review will provide a reference in the application of big defensins

~(265)Bh(Z=107)同位素的首次观测

在兰州的重离子加速器上用 2 6Mg离子束轰击 2 43 Am靶 ,产生了新同位素 2 65Bh .通过观测新同位素 2 65Bh和它的已知子核 2 61Db和 2 57Lr之间的α衰变的关联 ,实现了对新核素的鉴别 .实验中使用了一套新建立的具有数个探测器对的转轮收集探测系统 .将该系统用于特殊的母 -子核搜索模式 ,从而大大减少了本底 .共测得了 8个 2 65Bh的α衰变关联事件 ;同时 4个已知核 2 64Bh的衰变关联事件也被鉴别出来 .实验测得 2 65Bh的α衰变能量为 (9.2 4± 0 .0 5 )MeV ,半衰期为 0 .94 + 0 .70-0 .3 1s

新同位素~(265)Bh(Z=107)的合成证据

利用兰州重离子加速器提供的26Mg离子束轰击243Am靶, 产生了新同位素265Bh. 实验中用氦喷技术对产物进行传输, 并用一套具有数对探测器组的转轮收集探测系统对产物进行收集和测量. 通过观测265Bh与它的衰变子核261Db及257Lr之间的α衰变的关联, 实现了对新核素的鉴别. 实验测得265Bh的α衰变能量为(9. 24±0. 05)MeV, 半衰期为 0. 94+0. 70 0. 31 s

利用α关联衰变链鉴别新同位素_(107)~(265)Bh

主要介绍了合成和鉴别107号元素的新同位素265Bh的实验装置、实验方法以及实验结果.目标核265Bh是由能量为135MeV的26Mg离子轰击243Am靶,通过融合蒸发反应而产生.反应产物首先由He jet系统传输到装有数个探测器对的转轮收集测量系统,然后依靠母子核遗传关系通过观察新同位素和它们已知子核261Db和257Lr之间的α衰变的关联,来实现对新核素的鉴别.实验测得265Bh的α衰变能量为(9.24±0.05)MeV, 半衰期为0.94+0.70-0.31s.从该实验得出的265Bh的α衰变能量和半寿命能够与理论预言一致

大连极紫外相干光源

先进光源的发展在前沿科学研究中发挥的作用越来越重要。近十年来,飞速发展的自由电子激光技术为科学家们提供了探索未知世界、发现新科学规律和实现技术变革的重要工具。建成的大连极紫外(EUV)相干光源的运行波段为50~150nm,单脉冲能量大于100μJ,且可提供10-12 s和10-13 s量级的超快激光脉冲,是我国第一台自由电子激光用户装置,并且是国际上唯一运行在极紫外波段的自由电子激光用户装置,在世界范围内为用户提供具有高峰值亮度和超短脉冲的极紫外激光。大连EUV相干光源是由国家自然科学基金委资助、由中国科学院大连化学物理研究所和上海应用物理研究所共同承担的重大科学仪器研制项目,目标是打造一个以先进极紫外光源为核心、主要用于能源基础科学研究的光子科学平台

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel