Exploring Particle Dispersion and Charge Percolation in Suspension Electrodes: Bridging Electrochemical Performance and Rheology

对可持续能源和获得清洁水的日益关注促使人们需要发展有效和具有成本效益的技术，这些技术可以迅速扩大规模，以满足日益增加的需求。在最近的进展中，可流动悬浮电极的概念已经成为解决大规模储能和水净化挑战的一种非常有前途的方法。悬浮电极可以广义地定义为悬浮在液体电解质中的电化学活性材料的浆液。这些电极的性能受流动条件和系统设计的影响，这使得它们比传统电极更具挑战性。该项目旨在解决与这些电极的电化学性能和流动特性相关的一些悬而未决的问题，以帮助确定这种新型电极的最佳工程设计选择。因此，将进行大量的研究来探索和揭示这些电极的流动性与电化学性能之间的复杂关系。从这些研究中获得的新发现和新知识将有利于新兴储能和水处理技术的研究，并有助于开发利用这种新型电极的可扩展新技术。该项目还将提供重要的机会，将研究的影响扩展和扩大到更大的社会。它将以能源为主题的活动为目标，帮助加强对广大学生的教育，吸引年轻人才在国家战略利益领域从事STEM职业。悬浮电极依靠体积跨越的导电粒子网络来有效地促进电荷传输和最小化欧姆损失。这种粒子网络预计对电极粘度的影响最小，因此在操作过程中泵送产生的能量损失可以最小化。电导率和粘度之间的这种权衡造成了关键的设计限制；因此，改善这些可流动电极性能指标的最合理途径是探索设计具有所需电化学性能和匹配流变特性的悬浮液的方法。在这种需求的推动下，该项目的目标是建立一个新的基于物理的框架，用于合理设计高性能悬浮电极，优化粒子网络，增强流动性和易于电荷传输。为了实现这一目标，这项工作的一个关键目标将是量化控制粒子相互作用、粒子聚类和这些电极中电荷传输的渗透网络演变的关键可调参数。这种理解将能够直接控制粒子网络，并提供一定程度的关键属性可调性，以达到最佳的工程设计选择。将进行一系列假设驱动的研究，为这些电极中的材料、加工、粒子相互作用、电荷转移和渗透过程提供新的见解。预计这些研究将有助于扩大知识在胶体科学通过调查一个独特的类悬浮液为更广泛的研究社区。这项研究的结果也有望帮助设计各种应用的功能性油墨。由此产生的发现和从这项工作中获得的新知识也将有利于新兴海水淡化技术的研究，并有助于为这些应用制定优化的悬浮液。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Growing concerns over sustainable energy sources and access to clean water have prompted the need for development of efficient and cost-effective technologies that can be readily scaled to meet the increasing demand. Among the recent advances, the concept of flowable suspension electrodes has emerged as a highly promising approach for addressing the challenges in large-scale energy storage and water purification. Suspension electrodes can be broadly defined as a slurry of electrochemically active materials suspended in a liquid electrolyte. Performance of these electrodes is governed by the flow conditions and the system design, making them significantly more challenging to characterize than conventional electrodes. This project is designed to address some of the open questions related to the electrochemical performance and the flow characteristics of these electrodes to help determine optimal engineering design choices for this new class of electrodes. Accordingly, a number of studies will be conducted to explore and reveal the complex relation between the flowability and the electrochemical performance of these electrodes. The resulting discoveries and new knowledge gained from these studies will benefit research on emerging energy storage and water treatment technologies and help develop new scalable technologies that utilize this new class of electrodes. This project will also offer significant opportunities to extend and amplify the impact of the research to a larger society. It will target energy-themed activities and help enhance the education of a broad range of students, attracting young talented people to STEM careers in the areas of strategic national interests.Suspension electrodes rely on volume-spanning networks of conducting particles to effectively facilitate charge transport and minimize ohmic losses. Such particle networks are expected to have a minimum impact on the viscosity of the electrode so that the energy losses incurred by pumping can be minimized during operation. This trade-off between the electrical conductivity and the viscosity imposes critical design limitations; therefore, the most rational path forward to improve the performance metrics of these flowable electrodes is to explore ways to design suspensions that have the desired electrochemical properties with matching rheological characteristics. Motivated by this need, the objective of this project is to establish a new physics-based framework for rational design of high-performance suspension electrodes with optimized particle networks that enable enhanced flowability and facile charge transport. Toward this goal, a key objective of this work will be to quantify the critical tunable parameters that govern particle interactions, particle clustering, and the evolution of percolation networks for charge transport in these electrodes. This understanding will enable direct control of the particle networks and offer a certain level of tunability of the key properties to arrive at the optimal engineering design choices. A set of hypothesis-driven studies will be conducted to provide new insights into materials, processing, particle interaction, charge transfer, and percolation processes in these electrodes. It is anticipated that these studies will help expand the knowledge in colloidal science by investigating a unique class of suspensions for a broader research community. Findings of this study are also expected to aid in the design of functional inks for a variety of applications. The resulting discoveries and new knowledge gained from this work will also benefit research on emerging water desalination technologies and help formulate optimized suspensions for these applications.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.