SusChem: Development and fundamental investigation of high capacity cathode materials for high energy and low cost Na-ion batteries

该项目涉及用于运输的储能系统以及风能和太阳能发电技术产生的电力的间歇性供应。这些应用的一个潜在解决方案是使用钠离子电池，该电池利用广泛可用的国内资源。钠离子电池具有与锂离子电池类似的功能机制，但成本更低，因为钠比锂丰富得多。目前，钠离子电池的性能主要受正极材料的限制。现有的钠离子电池正极材料大多存在容量低、循环寿命短的问题。此外，在这些电极材料中通常使用诸如钴和镍的贵金属，这增加了成本。该项目旨在开发基于最丰富的元素之一锰的氧化物的低成本和高性能的新型阴极材料。阴极材料的设计采用了来自基础科学的策略，使阴极能够以最小的性能退化进行数百次充放电循环。对于教育影响，该项目将推进固态化学和电化学领域的知识。该项目的进展和新发现将纳入本科和研究生课程，并通过暑期课程向高中教师和学生传播。该项目的成果将加快钠离子电池的开发和商业化，从而显著提高储能技术的可持续性。在连续的电化学充放电循环中阴极电极材料中的晶体结构的稳定性是在钠离子电池中获得长循环寿命的关键。本项目主要研究具有层状结构的新型钠锰氧化物正极材料的合理设计。新的策略被用来稳定它们的结构，通过掺杂选定的元素到锰网站。预期掺杂有效地延迟或减轻钠嵌入和脱嵌过程期间的相变，因此允许高容量和长循环寿命。所设计的材料将被合成和电化学测试。多种先进的表征方法，如原位X射线衍射，将被用来调查在电化学循环过程中的材料的晶体结构的变化。通过解释合成，电化学测试和结构表征的结果，将揭示层状阴极材料的结构稳定性，验证假设，并验证和进一步完善材料设计策略，以指导下一代高性能钠离子电池阴极电极材料的开发。

This project addresses energy storage systems for the transportation and the intermittent supply of electricity generated by wind and solar power technologies. One potential solution for these applications is the use of sodium-ion batteries that utilizes widely available and domestic resources. Sodium ion batteries have similar functioning mechanisms as lithium ion batteries but cost less, as sodium is much more abundant than lithium. Currently, the performances of sodium ion batteries are mainly limited by the cathode electrode materials. Most of the existing cathode materials of sodium ion batteries suffer from low capacity and short cycle life. In addition, precious metals such as cobalt and nickel are typically used in these electrode materials, which increases the cost. This project aims to develop low cost and high performance novel cathode materials based on the oxides of one of the most abundant elements, manganese. The cathode materials are designed using strategies derived from fundamental science that allow the cathode to be charge-discharge cycled for hundreds of times with minimal performance degradation. For educational impacts, the project will advance knowledge in the fields of solid state chemistry and electrochemistry. The progress and new findings of the project will be included in undergraduate and graduate courses and disseminated to high school teachers and students through summer programs. The outcomes of the project will expedite the development and commercialization of sodium ion batteries, and therefore significantly improve the sustainability of energy storage technologies. The stability of the crystal structure in cathode electrode materials in continuous electrochemical charge-discharge cycles is key to obtain long cycle life in sodium ion batteries. This project focuses on rational design of novel sodium manganese oxide cathode materials with layered structures. Novel strategies are used to stabilize their structure by doping selected elements into the manganese sites. The doping is expected to effectively delay or mitigate the phase transitions during the sodium intercalation and deintercalation processes, therefore allowing high capacity and long cycle life. The designed materials will be synthesized and electrochemically tested. Multiple advanced characterization methods such as in situ X-ray diffraction will be used to investigate the changes of the crystal structure of the materials during electrochemical cycling. By interpreting the results from synthesis, electrochemical tests, and structure characterizations, insights on the structural stability of the layered cathode materials will be revealed, the hypotheses will be validated, and the materials design strategies will be verified and further refined to guide the development of next generation high performance cathode electrode materials for sodium ion batteries.