GOALI: A Comparative Study of Electrochemical Codeposition with In-Situ Electron Microscopy

在IBM的支持和合作下，本提案打算使用各种工具，实时研究电化学共沉积的纳米级力学。对于锌-铋和铋-碲共沉积系统，将应用恒电位、恒流和脉冲控制，同时对沉积结构的发育形态进行成像-在原位，在液体电解质中-具有良好的时间分辨率（每秒30张图像）和空间分辨率（优于20nm）。这将为电化学处理过程中纳米尺度沉积形态的演变提供独特的计量信息。本研究解决了当前对共沉积过程的理解中的一个重大空白：在不同的过程控制制度和电解质组成下，形态和化学计量学是如何变化的。本提案中概述的两种模型共沉积系统有希望在能源相关技术中使用。在电化学存储结构中，锌阳极长期以来一直具有吸引力，原因是1)与空气或低成本阴极配对时能量密度高，2)丰度高，3)成本低。到目前为止，由于枝晶结构的倾向，二次锌阳极很难实现。众所周知，铋可以抑制工作锌电池中的氢析出，并且添加铋可以延长保质期，因此铋是一种对镀锌结构感兴趣的添加剂。对于另一种应用，轻微的非化学计量的碲化铋是热电装置的主要结构，包括冷却装置和发电机。热电的效能是由互补的p型和n型结构的相对化学性质决定的。在实验室之外，拟议的研究将服务于原位显微镜的核心主题，并为高中和本科生提供种子讲座，演示和在线媒体。

This proposal intends to use a variety of tools, with support and collaboration from IBM, to study the nanoscale mechanics of electrochemical codeposition in real time. For the zinc-bismuth and bismuth-tellurium codeposition systems potentiostatic, galvanostatic, and pulsed control will be applied while simultaneously imaging the developing morphology of the deposited structure - in situ, within the liquid electrolyte - with good temporal resolution (30 images per second) and spatial resolution (better than 20nm). This will provide unique metrological information on the evolution of the deposit morphology at the nanoscale during electrochemical processing. This study addresses a significant gap in current understanding of codeposition processes: how morphology and stoichiometry vary under different process control regimes and electrolyte compositions.The two model codeposition systems outlined in this proposal have promise for use in energy related technologies. In electrochemical storage structures zinc anodes have long been attractive for reasons of 1) high energy density when paired with air or low-cost cathodes, 2) abundance, and 3) cost. To date secondary zinc anodes have been difficult to achieve due to a tendency toward dendritic structures. Bismuth is known to suppress hydrogen evolution in a working zinc battery and is added to increase shelf life, thus is an additive of interest to plated zinc structure. For another application, slight non-stoichiometries of bismuth telluride are the workhorse structures for thermoelectric devices, both cooling devices and electrical generators. The efficacy of the thermoelectric is determined by the relative chemistries of the complementary p and n type structures. Outside the laboratory the proposed research will serve a core topic of in-situ microscopy and seed lectures, demonstrations and online media for high school and undergraduate students.