Collaborative Research: Co-Extrusion of Organic-Inorganic Colloidal Inks for Energy Conversion Applications

能量存储（电池）和能量转换系统（燃料电池）由通常称为膜电极组件的平面分层结构组成。这些系统的主要限制之一是与制造相关的多步骤材料处理。挤压制造方法提供了一次联合收割机多种材料系统的机会，用于电化学系统的集成和工程部件开发。实现这一目标的关键挑战之一是能够生产具有受控特性的均匀部件的胶体油墨的工程设计。在这个项目中，胶体油墨，可以被描述为半固体或半液体，由铂涂层碳颗粒在聚合物基地。这项工作将研究这些复杂的油墨在挤出条件下的行为，以及它们如何与其他共挤出油墨相互作用。对胶体油墨的共挤出加工的基本理解将可能使电化学系统中常见的多层结构和组件的简便和可扩展的制造方法成为可能。此外，胶体共挤出在新型复合材料、有机电子、热电、光电子、生物材料和电池的制造中具有广泛的应用。除了提供研究生和本科生的研究经验，该项目将有助于扩大在纳什维尔和亚特兰大地区的K-12计划的制造业教育。复杂的材料系统很少使用基于共挤出的方法加工，这是由于机械和流体引起的不稳定性引起的固有困难。这些不稳定性是有据可查的，并广泛了解单组分挤出加工（如聚合物），但有有限的研究，探测多组分胶体材料。本论文的研究目的是探讨共挤出过程中软硬胶体之间的相互作用。这项工作特别试图了解油墨中组分之间的相互作用如何影响粘弹性，并促进或抑制油墨混合或分层机制。这项工作将利用先进的表征技术（散射和显微镜）来探测胶体结构信息，并定义独特的本构方程来描述挤出胶体油墨的功能特性。 此外，这些本构关系将用于工程胶体油墨，促进挤出过程中的界面稳定性。这项工作是根本性的，这项工作的产品是相关的制造业社区以及流变学，电化学和胶体科学社区。

Energy storage (batteries) and energy conversion systems (fuel cells) are composed of planar, layered structures often referred to as membrane electrode assemblies. One of the primary limitations with these systems is the multi-step materials processing associated with manufacturing. Extrusion manufacturing methods offers the opportunity to combine multiple materials systems at once for integrated and engineered part development for electrochemical systems. One of the key challenges in achieving this is the engineering of colloidal inks capable of producing uniform parts with controlled properties. In this project, colloidal inks, which can be described as semi-solid or semi-liquid, consist of platinum coated carbon particles in a polymeric base. The work will investigate how these complex inks behave under extrusion conditions, and how they interface with other co-extruded inks. A fundamental understanding about co-extrusion processing of colloidal inks will potentially enable facile and scalable manufacturing methods for multi-layered structures and components common in electrochemical systems. Moreover, colloidal co-extrusion has broad application in the manufacturing of novel composite materials, organic electronics, thermoelectric, photovoltaics, bio-materials, and batteries. In addition to providing graduate and undergraduate students research experiences, this project will contribute towards broadening manufacturing education in K-12 programs in the Nashville and Atlanta areas. Complex material systems are rarely processed using co-extrusion based approaches due to the inherent difficulties which arise due to mechanical and fluid induced instabilities. These instabilities are well documented and broadly understood for single component extrusion processing (e.g. polymers), but there have been limited studies that probe multi-component colloidal materials. The research objective of this work is to explore the interactions between soft and hard colloids during co-extrusion processes. The work specifically seeks to understand how interactions between components in an ink affects viscoelastic properties and promote or dampen ink mixing or delamination mechanisms. This work will utilize advanced characterization techniques (scattering and microcopy) to probe colloid structure information and define unique constitutive equations to describe functional properties in extruded colloidal inks. Moreover, these constitutive relationships will be used to engineer colloidal inks that promote interfacial stability during extrusion processes. This work is fundamental in nature and the product of this work is relevant to the manufacturing community as well as the rheological, electrochemical, and colloidal science communities.