CAREER: Computational Design of High-Performing V2O5 Cathodes for Zn-ion batteries

锂离子电池具有高能量密度、高放电电压和相对较低的成本，已成为各种应用的首选电池，包括便携式消费电子产品、混合动力和全电动汽车以及电网规模的储能。然而，这些电池也有缺点：潜在的安全问题以及对锂和正极材料可用性的日益关注。作为一种替代方案，以钒氧化物为正极材料的锌离子电池已经成为电网规模存储的一种有前途的安全且经济高效的选择。凭借这份CAREER奖，PI将采用最先进的计算建模方法来设计最稳定的锌离子阴极材料，从而提高锌离子电池的性能和寿命。这样的进步将使社会受益，因为更多的间歇性绿色能源，如风能和太阳能，可以以经济、可靠和安全的方式纳入电网。该奖项还支持PI的教育和外展活动。该项目将培养高中生、本科生和研究生的研究能力，提高他们的计算能力，使他们更好地理解和相信科学方法，并提高批判性思维、解决问题和展示结果等技能。通过这种培训，学生将更好地在各种学术和非学术职业中取得成功。教育部分将直接促进STEM领域的多样性，特别是物理领域，通过结合外展，为高中生和本科生提供研究机会，以及增加被博士课程录取的代表性不足的学生。对于电网规模的存储，以钒氧化物为正极材料的锌离子电池已经成为锂离子电池的一种有前途的安全和经济的替代品，但是对钒氧化物性质的基本知识仍然缺乏，这阻碍了该领域的进展。该奖项支持理论和计算研究和教育，旨在促进对钒氧化物在生长（点缺陷和缺陷复合物）和脱/插层（缺陷和缺陷、锌离子和极化子之间的相互作用）过程中发生的原子过程的物理和化学的基本理解。该团队将研究共插层，同时考虑干燥和含水条件。降解过程，如有害的相变和结构降解，也将被研究，并将探索故意掺杂以潜在地减轻这些过程。该团队将采用混合功能第一性原理计算、分子动力学（MD）模拟、机器学习高斯过程来加速MD模拟和相图的构建，并采用“彩色”电荷方法来加速插层和脱插层的MD模拟。所获得的基本知识有望导致合理的设计规则，以提高电池性能，并通过在原子尺度上提供对阴极物理和化学的见解来阐明实验观察。该项目由材料研究部的凝聚态物质和材料理论项目和促进竞争研究的既定计划（EPSCoR）共同资助。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。

NONTECHNICAL SUMMARYLithium-ion batteries, with their high-energy density, high-discharge voltage, and relatively low cost, have been the battery of choice for a wide variety of applications, including portable consumer electronics, hybrid- and all-electric cars, and grid-scale energy storage. However, these batteries also come with drawbacks: potential safety issues and growing concerns regarding the availability of lithium and of the cathode materials. As an alternative, zinc-ion-based batteries with vanadium oxides as cathode material have emerged as a promising safe and cost-efficient option for grid-scale storage. With this CAREER award, the PI will employ state-of-the-art computational modeling approaches to design the most stable cathode material for zinc ions, thereby improving the performance and longevity of zinc-ion batteries. Such progress will benefit society because more intermittent green energy sources, like wind and solar, can be included in the electricity grid in a cost-efficient, reliable, and safe manner. This award also supports the PI's educational and outreach activities. The PI will train high school, undergraduate, and graduate students in research competencies, increase their computational proficiency, provide them with a better understanding of and confidence in the scientific method, and improve skills like critical thinking, problem solving, and presenting results. With this training, students will be better equipped to succeed in a wide variety of academic and non-academic careers. The educational components will directly contribute to an increase in the diversity of the STEM fields, and of physics in particular, through a combination of outreach, research opportunities for high school and undergraduate students, and an increase of underrepresented students admitted to PhD programs. TECHNICAL SUMMARYFor grid-scale storage, Zn-ion-based batteries with vanadium oxides as cathode material have emerged as a promising safe and cost-efficient alternative to Li-ion batteries, but fundamental knowledge of the properties of vanadium oxides is still lacking, which hinders progress in the field. This award supports theoretical and computational research and education with an aim to advance fundamental understanding of the physics and chemistry of the atomistic processes taking place in vanadium oxides during growth (point defects and defect complexes) and during de/intercalation (defects and interactions between defects, Zn ions, and polarons). The team will study co-intercalation, considering both dry and aqueous conditions. Degradation processes, such as detrimental phase transitions and structural degradation, will also be investigated, and deliberate doping will be explored to potentially mitigate these processes. The team will employ hybrid functional first-principles calculations, molecular dynamics (MD) simulations, machine-learned Gaussian Processes to accelerate MD simulations and the construction of phase diagrams, and a "color" charge method to accelerate MD simulations of intercalation and deintercalation. The fundamental knowledge gained is expected to lead to rational design rules to improve battery performance and shed light on experimental observations by providing insights into the physics and chemistry of the cathode at an atomic scale.This project is jointly funded by the Condensed Matter and Materials Theory program of the Division of Materials Research and the Established Program to Stimulate Competitive Research (EPSCoR).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.