RII Track-4: Understanding Reaction-Transport Coupling in High-Temperature Thermochemical Energy Storage Systems

太阳能热化学储能（TCES）有潜力发展成为一种变革性技术，为化石燃料枯竭和人为气候变化问题提供综合解决方案。聚光太阳能通过物质和能量变化的化学反应和物质循环，不断地转化为化学能，从而用于发电。TCES具有按需供电和无需储能的内在优势，可以缓解太阳能发电的间歇性和波动性。尽管基于热力学和反应性测试的材料发现在控制良好的平衡环境中取得了重大进展，但它们的性能远远不能令人满意，因为转换效率低，并且在循环过程中反应性显著下降。NSF EPSCoR RII Track-4奖学金项目为PI的建模小组与密歇根州立大学机械工程系的实验组合作提供了机会，研究和理解TCES过程中的基本反应-输运相互作用，这对于设计和测试下一代TCES材料至关重要。该项目的支持也将用于帮助密西西比州立大学招收代表性不足的学生。本奖学金项目的目标是基于PI团队在孔隙尺度建模方面的合作，以及在东道国材料测试方面的实验组之间的合作，了解和量化高温太阳能热化学储能（TCES）材料和结构中的基本反应-输运耦合。孔隙尺度模型将用于模拟反应-输运耦合，微计算机断层扫描（micro-CT）扫描将用于跟踪结构变化。研究任务包括孔隙尺度输运建模、材料表征和多周期测试，将揭示最先进的TCES材料的基本反应-输运相互作用。他们还将建立反应材料设计的基本原理和方案，并提供新材料性能的定量预测和实验演示。通过计算模拟和实验演示，该项目将为深入了解复杂、非平衡环境下的微尺度化学-输运相互作用提供知识基础。该项目的广泛影响将为下一代TCES材料设计和完成实验方案开发提供指导，以最大限度地提高能量存储密度。此外，虽然该项目侧重于理解能量存储的热化学循环，但材料和结构的协同数值模拟和实验研究也适用于其他广泛的高温气固反应，如太阳能热化学燃料生产、化学环燃烧、空气分离、生物质/废物气化和蒸汽重整。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。

Non-Technical Abstract Solar thermochemical energy storage (TCES) has the potential to develop into a transformative technology that offers a combined solution to the problem of the depletion of fossil fuels and anthropogenic climate change. With chemical reactions that show both changes of matter and energy and material cycling, concentrated solar power is continuously converted into chemical energy that can be consequently used for power generation. TCES has the intrinsic advantage of the ability to provide energy upon demand and store energy when there is no demand, thus it can mitigate the intermittency and fluctuation of solar power. Although significant progress has been made in materials discovery based on thermodynamics and reactivity tests in well controlled equilibrium environments, their performance is shown to be far away from satisfactory as witnessed by low conversion efficiencies and substantial reactivity degradation over cycles. This NSF EPSCoR RII Track-4 fellowship project provides the opportunity for the PI's modeling group to collaborate with the experimental group in the Department of Mechanical Engineering at Michigan State University to investigate and understand the fundamental reaction-transport interactions in TCES processes that are essential for designing and testing next-generation TCES materials. Support from this project will also be leveraged to help recruit underrepresented students at Mississippi State University. Technical Abstract The goal of this fellowship project is to understand and quantify the fundamental reaction-transport coupling in high-temperature solar thermochemical energy storage (TCES) materials and structures based on the collaboration between the PI's group on pore-scale modeling and the experimental group at the host site on materials testing. A pore-scale model will be applied to simulate the reaction-transport coupling, and micro-computed tomography (micro-CT) scans will be employed to track the structural changes. The research tasks including pore-scale transport modeling and material characterization and testing over multiple cycles will reveal the fundamental reaction-transport interactions for state-of-the-art TCES materials. They will also establish the rationale and protocol for reactive material design, and provide quantitative prediction and experimental demonstration of new material performance. Through both computational simulation and experimental demonstration, the project will deliver a knowledge base for an in-depth understanding of the microscale chemistry-transport interactions in complex, non-equilibrium environments. The broader impacts of this project will provide guidance to the community for next-generation TCES material design and complete experimental protocol development to maximize the energy storage density. Moreover, while this project focuses on the understanding of thermochemical cycles for energy storage, the collaborative numerical modeling and experimental investigation of materials and structures are also applicable to a broad spectrum of other high-temperature gas-solid reactions such as those for solar thermochemical fuel production, chemical looping combustion, air separation, biomass/waste gasification, and steam reforming.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.