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

Propulsive performance of complex flapping foils

以NACA0006翼型为基准翼型,将其前缘部分更换为相对最大厚度较大的NACA0008、NACA0010、NACA0015和NACA0020翼型前缘部分,组成混合翼型。通过流体仿真软件Fluent14.5对基准翼型及混合翼型进行数值模拟计算,并分析扑翼运动的推进性能。结果表明：混合翼型相较于基准翼型对扑翼运动推力系数和推进效率有显著提高

熔盐法合成纳米层状Sc_(2)SnC MAX相(英文)

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土のう構造体を用いた道路盛土の新たな耐震補強工法に関する実大震動台実験 －地震災害後の道路の早期復旧と中長期的な維持に向けての検証－

日本全国に広がる道路盛土の多くは，抜本的に，維持管理を要することはよく知られている．日本国内には耐震性の低い道路盛土が多数存在し，盛土材料の質が低く，不十分な締固めにより施工されていることが大きな理由の1つとなっている．これらの問題を解決するため，道路管理者にとっての緊急課題として，効率的かつ経済的な耐震補強工法の開発が必要であると考えた．そこで，本研究において，現地の盛土材を再利用することを目的に，大型土のうを用いた道路盛土の耐震補強方法を提案した．本研究資料では，既設盛土の法先部に複数設置された土のう構造体の補強効果を検証するため，Ｅ－ディフェンスにおいて実大道路盛土の震動台実験を実施し，その結果を中心に報告している．一連の実験結果から，定性的ではあるが，土のう構造体の補強効果による盛土の耐震性向上の可能性が確認された．It is well known that many of the existing road embankments spreading across Japan require drastic maintenance, because their earthquake resistance is considerably questionable due to the poor quality of the embankment materials used and insufficient compaction. In order to solve these problems, it is important to develop efficient and high cost-performance methods as an urgent task for engineers in charge of road management. Therefore, the authors proposed a seismic reinforcement method for road embankments by using flexible container bag that can reuse local embankment materials. In this study, a series of shake table tests on a full-scale road embankment was conducted at E-Defense in order to verify the reinforcement effects of the flexible container bag structures installed at the toe of the embankment. Based on the results obtained from the shake table tests, it was qualitatively confirmed that the flexible container bag structures can improve seismic resistance of the whole embankment