Engineering Fuel Cell Electrodes to Overcome Ion Transport Limitations using Low-cost, Efficient Lignin-based Ionomers

为了减少温室气体排放，需要环保、经济的电动汽车技术。一个很有前途的解决方案是质子交换膜燃料电池（PEMFC），这是一种使用氢作为燃料的电化学技术。然而，目前的pemfc使用的是一种名为Nafion的离子导电聚合物，价格昂贵且不环保。最重要的是，Nafion不能有效地在薄层（覆盖催化剂和电极）中传输质子，这对PEMFC的性能产生了负面影响，并限制了实际应用。该项目旨在通过使用一种新型的环保、高效离子导电聚合物来解决这些成本、性能和环境问题。这些聚合物将从木质素中提取，木质素是植物细胞壁中含量第二高的天然聚合物，也是农场、纸浆和造纸工业以及生物炼制的废弃副产品。在这个项目中，PI将使用来自植物的木质素来制造离子导电聚合物，并检查它们在薄层和界面中传输质子的能力，比如在pemfc中发现的那些。该项目是使基于木质素的离子导电聚合物取代Nafion的第一步，使PEMFC汽车在效率和成本上具有电池动力汽车的竞争力。该项目将向能源研究界介绍“使用绿色材料的绿色能源”的新概念，并为未来多元化的能源劳动力培训研究生、本科生和高中生。该研究还将辅以数据驱动的外展项目，以支持内布拉斯加州的能源素养，将游戏化融入课程以激发学生的批判性思维，吸引K-12学生和公众扩大STEM参与，并促进所有年龄段人群的能源教育。该项目的目标是通过利用木质素衍生的离子单体来克服离子传输限制，这是限制质子交换膜燃料电池（PEMFCs）采用的主要科学挑战。该项目将研究如何通过使用木质素基离聚体和操纵亚微米厚离聚层基底附近的化学、分子和方向景观来促进界面离子传输。该项目将通过(1)阐明由一系列木质素基离子单体组成的薄膜和催化剂层模拟系统中的界面质子传输特性，为加速界面电化学过程开辟新的途径；(2)利用木质素基离子单体设计界面，揭示其在深度特异性离子传输特性中的作用；(3)研究基于木素磺酸离聚体的电极模拟薄体系中的质子传输如何受到界面润湿、化学成分、离子域特性、纳米结构和粘弹性特性的控制。所获得的知识将为理解和加速界面电化学过程铺平新的道路，为设计具有成本效益，环保和高效的能量转换/存储设备提供动力，促进被忽视的生物质木质素的创新方法，并有助于生物和能源经济。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。

Eco-friendly, affordable technologies for electric cars are needed to reduce greenhouse gas emissions. One promising solution is the proton exchange membrane fuel cell (PEMFC), an electrochemical technology that uses hydrogen as fuel. However, current PEMFCs use an ion-conducting polymer, called Nafion which is expensive and not eco-friendly. Most importantly, Nafion fails to transport protons efficiently in thin layers (coating the catalyst and electrode) which negatively impacts PEMFC performance and limits real world applicability. This project aims to address these cost, performance, and environmental concerns by using a new class of eco-friendly, efficient ion-conducting polymers. These polymers will be derived from lignin, the second most naturally abundant polymer that is found in plant cell walls and a waste byproduct of agricultural farms, pulp and paper industries, and biorefineries. In this project, the PI will use lignin from plant sources to make ion-conducting polymers and examine their ability to transport protons in thin layers and interfaces, such as those found in PEMFCs. This project is the first step to enable lignin-based ion-conducting polymers to replace Nafion, make PEMFC vehicles efficient and cost competitive to battery-powered vehicles. This project will introduce the energy research community to a new concept “Green Energy using Green Materials” and enable training of graduate, undergraduate, and high school students for a future diversified energy workforce. The research will also be complemented by data-driven outreach programs to support energy literacy across Nebraska, integrate gamification into courses to stimulate student critical thinking, engage K-12 students and the general public to broaden STEM participation, and facilitate energy education for people of all ages. The goal of this project is to overcome ion transport limitation, a major scientific challenge limiting the adoption of proton exchange membrane fuel cells (PEMFCs), by utilizing lignin-derived ionomers. The project will investigate how to boost interfacial ion transport by using lignin-based ionomers and manipulating the chemical, molecular, and orientational landscape next to the substrate of sub-micron-thick ionomer layers. The project will open new pathways to expedite interfacial electrochemical processes by (1) elucidating interfacial proton transport properties within thin films and catalyst layer mimicking systems made of a series of lignin-based ionomers; (2) engineering the interface using lignin-based ionomers to reveal their role on depth-specific ion transport properties; and (3) examining how proton transport in lignosulfonic acid ionomer-based electrode-mimicking thin systems is controlled by interfacial wetting, chemical composition, ionic domain characteristics, nanostructure, and viscoelastic properties. The gained knowledge will pave new ways to understand and expedite interfacial electrochemical processes, empower the design of cost-effective, eco-friendly, and efficient energy conversion/storage devices, promote innovative ways to valorize the neglected biomass lignin, and aid in both bio- and energy economy.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.