Highly active and durable core-corona structured bifunctional catalyst for rechargeable metal-air battery application

A new class of core-corona structured bifunctional catalyst (CCBC) consisting of lanthanum nickelate centers supporting nitrogen-doped carbon nanotubes (NCNT) has been developed for rechargeable metal-air battery application. The nanostructured design of the catalyst allows the core and corona to catalyze the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR), respectively. These materials displayed exemplary OER and ORR activity through half-cell testing, comparable to state of the art commercial lanthanum nickelate (LaNiO(3)) and carbon-supported platinum (Pt/C), with added bifunctional capabilities allowing metal-air battery rechargeability. LaNiO(3) and Pt/C are currently the most accepted benchmark electrocatalyst materials for the OER and ORR, respectively; thus with comparable activity toward both of these reactions, CCBC are presented as a novel, inexpensive catalyst component for the cathode of rechargeable metal-air batteries. Moreover, after full-range degradation testing (FDT) CCBC retained excellent activity, retaining 3 and 13 times greater ORR and OER current upon comparison to state of the art Pt/C. Zinc-air battery performances of CCBC is in good agreement with the half-cell experiments with this bifunctional electrocatalyst displaying high activity and stability during battery discharge, charge, and cycling processes. Owing to its outstanding performance toward both the OER and ORR, comparable with the highest performing commercial catalysts to date for each of the respective reaction, coupled with high stability and rechargeability, CCBC is presented as a novel class of bifunctional catalyst material that is very applicable to future generation rechargeable metal-air batteries.     

STEM characterization for lithium-ion battery cathode materials

This article briefly reviews the status and new progress on the characterization of popular cathode materials for lithium-ion batteries by scanning transmission electron microscopy (STEM) and presents some of our own research work in this field, especially the direct observation of light elements such as Li and H with atomic resolution using the annular bright-field imaging (ABF) technique. These results demonstrate that STEM combined with high-angle annular dark-field imaging, electron energy-loss spectroscopy (EELS) and ABF imaging is a powerful tool for investigation of the atomic level microstructure of various cathode materials and resolving many fundamental issues in the battery related research field and industries, such as the mechanism of capacity fading and diffusion behavior across the interface between electrode and electrolyte.     

Electrochemomechanical degradation of high-capacity battery electrode materials

Enormous efforts have been undertaken to develop rechargeable batteries with new electrode materials that not only have superior energy and power densities, but also are resistant to electrochemomechanical degradation despite huge volume changes. This review surveys recent progress in the experimental and modeling studies on the electrochemomechanical phenomena in high-capacity electrode materials for lithium-ion batteries. We highlight the integration of electrochemical and mechanical characterizations, in-situ transmission electron microscopy, multiscale modeling, and other techniques in understanding the strong mechanics-electrochemistry coupling during charge-discharge cycling. While anode materials for lithium ion batteries (LIBs) are the primary focus of this review, high-capacity electrode materials for sodium ion batteries (NIBs) are also briefly reviewed for comparison. Following the mechanistic studies, design strategies including nanostructuring, nanoporosity, surface coating, and compositing for mitigation of the electrochemomechanical degradation and promotion of self-healing of high-capacity electrodes are discussed.     

Na0.44MnO2颗粒尺寸对其作为水系钠离子电池正极性能的影响

水溶性钠离子电池是一种与锂离子电池相辅相成的技术,因其相对较低的成本、改善的安全性和环境友好的电解液而备受青睐。然而,较低的电极容量限制了这种电池的应用。Na_0.44MnO₂是一种用于钠离子电池的高容量阴极材料,其理论容量为121 mAh/g。文章研究了Na_0.44MnO₂的尺寸效应对阴极性能的影响。纳米棒通过热处理MnO₂纳米片前驱体制备而成,其尺寸通过CTAB和KMnO₄的比例进行调控。然后,Na_0.44MnO₂纳米棒被用作水溶性钠离子电池的活性材料。纳米棒阴极在1 C的初始循环中提供了60 mAh/g的容量,并在经过200个循环后保持了55 mAh/g,比Na_0.44MnO₂块状阴极高出37.5%。在高倍率的5 C下,该阴极在经过200个循环后仍能提供47 mAh/g的高容量。容量的增加归因于减小的电荷传递阻抗和纳米棒具有较高比表面积所带来的改善的钠离子扩散性能。

     

锂离子电池硅基负极材料研究进展

锂离子电池硅基负极材料由于具有高的理论比容量,低的脱嵌锂电位,与电解液反应活性低等优点而成为研究热点。本文综述了近年来硅基材料作为锂离子负极材料的研究进展,包括纳米硅、硅基薄膜、硅-金属复合材料、硅-碳材料,分析硅基材料作为锂离子电池负极材料的研究前景和发展方向。     

野战装备封存封套材料研究

研发性能优异的封套材料是装备集合封存技术成败的关键.对封套材料的阻隔机理进行了系统分析,论证了封套材料的技术指标,提出了典型封套材料的结构设计.     

锂离子电池负极材料研究进展

锂离子电池(LIB)因其无记忆效应、环境友好且自放电小等各项优异性能得到了相关研究者的重点关注.信息电子产品、电动汽车和智能电网的发展对高能量密度、长循环寿命和低成本的LIB产生了巨大需求.负极作为LIB的重要组成部分之一,其性能对电池整体的各项指标有重要影响,要求负极所应用的材料具有高比容量和优异的循环性能等特性.传...     

锂离子电池硬碳负极材料研究进展

硬碳具有嵌锂容量大,造价低,循环寿命长等优点,是制备高安全性锂离子电池负极潜在的优良材料。介绍了硬碳材料的结构、特性及其用途,并综述了硬碳材料改性的研究发展。     

锂离子电池纳米正极材料的研究进展

综述了近年来纳米技术在锂离子电池正极材料中应用的最新进展,重点阐述了纳米LiCoO2、LiMn2O4及LiFePO4等正极材料的制备及其性能.纳米正极材料的制备方法主要有溶胶-凝胶法、共沉淀法、模板法及水热法等,电极材料的纳微米化对锂离子电池的电化学性能和循环性能的改善有着显著的意义.     

Evaluating the performance of nanostructured materials as lithium-ion battery electrodes

The performance of the lithium-ion cell is heavily dependent on the ability of the host electrodes to accommodate and release Li＋ ions from the local structure. While the choice of electrode materials may define parameters such as cell potential and capacity, the process of intercalation may be physically limited by the rate of solid-state Li＋ diffusion. Increased diffusion rates in lithium-ion electrodes may be achieved through a reduction in the diffusion path, accomplished by a scaling of the respective electrode dimensions. In addition, some electrodes may undergo large volume changes associated with charging and discharging, the strain of which, may be better accommodated through nanostructuring. Failure of the host to accommodate such volume changes may lead to pulverisation of the local structure and a rapid loss of capacity. In this review article, we seek to highlight a number of significant gains in the development of nanostructured lithium-ion battery architectures （both anode and cathode）, as drivers of potential next-generation electrochemical energy storage devices.     

锂离子电池正极材料镍酸锂的合成

研究了锂离子正极材料镍酸锂（ＬｉＮｉＯ２）的合成条件,主要考查了原料Ｌｉ／Ｎｉ摩尔比、反应气氛、预处理工艺和热处理方式对产物的影响,是到了ＬｉＮｉＯ２的最佳合成条件：原料为ＬｉＯＨ．Ｈ２Ｏ和β－Ｎｉ（ＯＨ）２．Ｌｉ／Ｎｉ摩尔比为１．０５：１,反应气氛为氧气,预处理方式为混合球磨后压块成型,热处理方式为两次热处理,经Ｘ射线衍射分析,合成的镍酸锂为层状结构,经电化学测试,其具有优良的电化学性能。     

The design and selection of materials for a general purpose mechanical seal

The predominant requirements for mechanical seals for use on modern continuous process plants are reliability, safety and ease of fitting & maintenance. Many users do not have specific engineering skills to select specially designed seals for particular applications. Nor do they have the fitting skills on process plants to deal with complex mechanical seals which may have many individual components which require expert fitting on the plant itself. The need was therefore identified for a general purpose mechanical seal which was easy to select for a particular application, and was both safe and reliable in operation. This paper describes the design, testing, development and areas for application of the Flexibox FFET general purpose cartridge seal for standard metric and inch shafts and a wide range of process and industrial machines, handling liquids — as varied as water, oil, chemicals and slurries.     

反应型聚氨酯热熔胶的研究进展

反应型聚氨酯热熔胶因具有绿色环保、性能优异、应用广泛等特点,近年来成为胶黏剂领域的研究热点,得到了快速发展。简单介绍了反应型聚氨酯热熔胶的固化机理、特点和应用,综述了反应型聚氨酯热熔胶在聚氨酯预聚体、热塑性树脂、增粘树脂和添加剂等方面的研究进展,并对其发展前景进行了展望。     

采用空气气氛合成的锂镍钴氧正极材料的性能

用控制结晶法合成了类似球形、颗粒细小的(Ni0.8Co0.2)2(OH)2CO3*4H2O前驱体,对前驱体二次干燥后,再与LiOH*H2O混合、研磨高温烧结,在空气气氛下合成了LiNi0.8Co0.2O2正极材料.采用正交实验对反应时间及锂配比因素进行了优化;同时也进行了XRD、 EIS及SEM等相关表征研究.结果表明:在750℃下烧结时,当Li/(Ni+Co)配比为1.05,烧结15h时得到的锂镍钴氧化合物性能最优;在0.1C,2.7～4.3V的条件下充放电,首次放电比容量达到179.2mAh/g.循环10次后容量变为167mAh/g,容量保持率为93%.