Nanoscale Surface Adsorption and Disordering in Battery Materials

非技术描述：高功率锂离子电池在电动汽车甚至电网稳定系统中具有巨大的应用潜力。此外，在大都市地区采用插电式混合动力电动汽车通勤可以减少高达50%的二氧化碳排放。虽然许多传统的材料工程技术，如碳涂层、掺杂和粒度减小，已经被用来改善电池材料的性能，但要满足这些巨大的挑战，需要新的变革性的方法。该项目旨在开发一种非传统的方法，利用厚度自我调节的纳米级“表面相”来定制电池材料，以获得使用普通三维块状材料或纳米颗粒无法获得的优异性能。该项目还旨在通过将成熟的低温表面科学理论扩展到高温陶瓷材料来弥合基础界面科学中的一个重要空白。综合研究和教育活动对高中、本科生和研究生以及普通民众都有影响。技术细节：本项目的研究目标有两个。第一个(技术)目标是开发一种新的方法，利用纳米级的“表面相”来提高电池材料的倍率能力。与传统涂层相比，这些“表面相”具有几个优点：(A)它们在热处理后自发形成热力学平衡构型；(B)它们具有可通过改变热力学势能调节的自我选择或“平衡”厚度；以及(C)表面掺杂可以增加离子和电子的导电性，改善电化学循环过程中的形态稳定性，并抑制形成有害的厚固体-电解质界面层。这一新方法有望适用于各种氧化物基正极材料(包括许多新兴材料)以及一些负极材料的工程设计。第二个(科学)目标是使用电池材料作为模型系统，研究一种潜在的变革性概念，即利用纳米级的表面相来获得体相无法获得的特性，并通过建立陶瓷材料中高温表面吸附和无序的新理论来推进基础界面科学。广泛的影响活动包括让高中生参与暑期研究项目；组建一个多学科的本科生团队来开发免费访问的在线教育材料；以及在与能源相关的尖端研究和推广活动中指导博士生。

NON-TECHNICAL DESCRIPTION: High-power lithium ion batteries have great potential for applications in electric vehicles or even electrical grid stabilization systems. Moreover, adopting plug-in hybrid electric vehicles for commuting in metropolitan areas can reduce CO2 emission by as much as 50%. While many conventional materials engineering techniques, such as carbon coating, doping, and particle size reduction, have been used to improve the performance of battery materials, meeting the grand challenges demands new transformative approaches. This project aims to develop an unconventional approach to use nanoscale 'surface phases' of self-regulating thickness to tailor battery materials to achieve superior properties that are not attainable by using the normal three-dimensional bulk materials or nanoparticles. This project also aims to bridge an important gap in the fundamental interfacial science by extending the well-established low-temperature surface science theories to high-temperature ceramic materials. Integrated research and education activities have impacts on high school, undergraduate, and graduate students, as well as the general public.TECHNICAL DETAILS: The research objectives of this project are twofold. The first (technological) objective is to develop a new method of using nanoscale 'surface phases' to improve the rate capability of battery materials. Compared with the conventional coatings, these 'surface phases' have several advantages: (a) they form spontaneously upon annealing as the thermodynamic equilibrium configurations; (b) they exhibit a self-selecting or "equilibrium" thickness that is tunable by changing thermodynamic potentials; and (c) surface doping can be introduced to increase the ionic and electronic conductivity, improve the morphological stability during electrochemical cycling, and suppress the formation of the detrimental thick solid-electrolyte interface layers. This new approach is expected to be applicable for engineering a wide variety of oxide based cathode materials (including many emerging materials), as well as some anode materials. The second (scientific) objective is to use battery materials as model systems to investigate a potentially transformative concept of utilizing nanoscale 'surface phases' to achieve properties unattainable through bulk phases, and to advance to the fundamental interfacial science by establishing new theories of high-temperature surface adsorption and disordering in ceramic materials. Broad impact activities include involving high school students in summer research programs; assembling a multidisciplinary undergraduate team to develop free-access online educational materials; and mentoring doctoral students in both cutting-edge energy-related research and outreach activities.