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)由平面层状结构组成，通常称为膜电极组件。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组合多种材料系统的机会，用于电化学系统的集成化和工程化部件开发。实现这一目标的关键挑战之一是设计能够生产性能可控的均匀部件的胶体油墨。在这个项目中，胶体油墨可以被描述为半固态或半液态，由聚合物基中涂有铂的碳颗粒组成。这项工作将调查这些复杂的油墨在挤出条件下的表现，以及它们如何与其他共挤出油墨连接。对胶体油墨共挤出加工的基本了解将可能使电化学系统中常见的多层结构和组件的制造方法变得简单和可扩展。此外，胶体共挤出在新型复合材料、有机电子、热电、光伏、生物材料和电池等领域有着广泛的应用。除了为研究生和本科生提供研究经验外，该项目还将有助于扩大纳什维尔和亚特兰大地区K-12课程的制造业教育。由于机械和流体引起的不稳定性带来的固有困难，复杂材料系统很少使用基于共挤出的方法进行加工。这些不稳定性在单组分挤出加工(例如聚合物)中得到了很好的证明和广泛的理解，但探索多组分胶体材料的研究有限。本工作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。这项工作专门寻求了解油墨中各组分之间的相互作用如何影响粘弹性特性，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)来探测胶体结构信息，并定义独特的本构方程来描述挤压胶体油墨的功能性质。此外，这些本构关系将被用于设计胶体油墨，以促进挤出过程中界面的稳定性。这项工作本质上是基础性的，这项工作的成果与制造业以及流变学、电化学界和胶体科学界有关。

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.