北京交通大学“与大师面对面”名师讲坛系列活动

（机电学院，2016年春季第13周）

　　【主  题】：From MAX to MXene - From 3D to 2D （从3D MAX材料到2D MX烯的研究）

　　【主讲人】：Michel W. Barsoum 教授，美国德雷赛尔大学材料科学与工程学院

　　【时  间】：2016年5月25日（星期三）上午9：30-12：00

　　【地  点】：机电学院大会议室（机械工程楼Z802B）

　　【主  办】：研究生工作部

　　【承  办】：机电学院

　　【主讲人简介】：

　　Prof. Michel W. Barsoum - Distinguished Professor in the Department of Materials Science and Engineering at Drexel University - is an internationally recognized leader in the area of MAX phases. He is the author of two entries on the MAX phases in the Encyclopedia of Materials Science and the book, MAX Phases, published in 2013. He is also the author of Fundamentals of Ceramics, a leading textbook in his field. In 2011, he and Drexel colleagues selectively etched the A-group layers from the MAX phases to produce an entirely new family of 2D solids - they labeled MXenes - that have sparked global interest because of their potential in many applications, least of which is energy storage. With over 350 refereed publications, cited over 15,000 times and an ISI h index of 63, his work has been highly cited. In 2009 he made ISI's most highly cited authors' list. He is a fellow of the American Ceramic Society and the World Academy of Ceramics. In 2000 he was awarded a Humboldt-Max Planck Research Award for Senior US Research Scientists. Since 2008 he has been a visiting professor at Linkoping University in Sweden. He spent his last sabbatical year at Imperial College in London and the Grenoble Institute of Technology in Grenoble, France.

　　米歇尔. M. 巴索姆，美国德雷赛尔大学材料科学与工程学院杰出教授，国际公认的在MAX相材料研究领域的领跑者。他参与编写了《材料大百科全书》关于MAX相材料的两个完整部分，是2013年出版的《MAX相材料》一书的作者。他同时也是著名工具手册《陶瓷材料学》的作者。2011年，他带领的德雷赛尔大学研究组成功腐蚀掉了MAX相材料的A层部分，得到了一种新型2D产物，将其命名为MXenes，该研究引起了全球研究者的浓厚兴趣并引申出对该材料许多潜在的应用价值，特别是在储能材料领域。他的科研成果超过350项，被引用率超过15000次，发表文章总影响因子和高达63。2009年他被评为ISI最高引用率作者之一。他担任美国陶瓷学会和世界陶瓷学会的院士。2000年他获得美国高级科学家协会评出的普朗克科学研究奖。他还担任瑞典林雪平大学的客座教授。

　　【讲座简介】：

　　By now it is well-established that the layered, hexagonal carbides and nitrides with the general formula, M_n+1AX_n, (MAX) where n = 1 to 3, M is an early transition metal, A is an A-group (mostly IIIA and IVA) element and X is either C and/or N – sometimes referred to as polycrystalline nanolaminates because every basal plane is a potential deformation or delamination plane - combine some of the best attributes of metals and ceramics. They are excellent conductors of heat and electricity, damage and thermal shock tolerant and fracture toughness values as high as 15 MPa√m. Some are lightweight, stiff and have good creep and outstanding oxidation resistance. More recently we have shown that by simply immersing MAX phase powders, at room temperature, in HF the A-layers are selectively etched to produce 2D materials that we labeled MXenes to emphasize the loss of the A-group element and their similarities to graphene. Unlike hydrophobic graphene, MXenes are hydrophilic and behave as “conductive clays”, a hitherto unknown combination. MXenes such as Ti₂C, V₂C, Nb₂C and Ti₃C₂ can be used as electrode materials in lithium-ion batteries (LIBs) and supercapacitors (SC) as well as transparent conductive electrodes, with performances that are quite impressive. In all cases, when used as anodes in LIB, MXenes showed an excellent capability to handle high cycling rates. Flexible, additives-free electrodes of delaminated Ti₃C₂ showed reversible capacities of > 400 mAhg^-1 at 1 C and 110 mAhg^-1 at 36 C, the latter for > 700 cycles. SC's with volumetric capacitances of > 900 F/cm³ were obtained. The potential of using MXenes in energy storage, as transparent conductive electrodes, among many other applications will be highlighted.

　　目前早已被学界确定的具有通用化学式的M_n+1AX_n, (MAX材料)，n=1到3，M是过渡族金属，A是A主族（主要为IIIA和IVA组）元素，X是碳或氮元素的六方层状碳化物或氮化物，因为组成该材料的每个基础层均可以是其它层形成或分解而来，故有时也称其为多晶纳米层材料，该类材料兼具了金属和陶瓷的一些特质。其为电和热的优良导体，损伤和热震容限材料，其断裂韧性高达15MPa等。其中的部分材料还拥有轻量化、高硬度、良好的蠕变和优异的抗氧化性能。近来，该教授带领的课题组已经展示了通过利用HF酸在室温下对MAX材料粉末腐蚀来除掉A位结构进而得到了类似石墨烯结构的2D材料MXenes。不同于疏水型的石墨烯，MXenes为亲水型材料，其表现特性类似一种未知材料“导电黏土”。MXenes 材料，诸如Ti₂C，V₂C，Nb₂C和Ti₃C₂，可以用作如锂离子电池、超级电容及透明导电电极等性能优异的电极材料。如上述所述，将MXenes用于锂离子电池的阳极，其可表现出优异的比容量来承载高周循环。此外，自由添加的分层Ti₃C₂电极还展现出可逆能力，其在1C倍率下的放电比容量超过 400 mAhg^-1，在36C倍率下的放电比容量超过110 mAhg^-1，且后者循环周次超过700。并且，利用该材料制得容量超过900F/cm³的超级电容已经实现。通过利用MXenes制备诸如透明导电电极在内的储能材料及一些其它应用将会拥有一个非常光明的前景。