CAREER: Engineering electrochemical reversibility in disordered materials for high energy density batteries

职业：为高能量密度电池设计无序材料的电化学可逆性

• 批准号: 2044602
• 负责人: Joshua Gallaway
• 金额: $ 51.01万
• 依托单位: Northeastern University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-03-01 至 2026-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2044602&HistoricalAwards=false
• 关键词: CAREER; Engineering; electrochemical; reversibility; disordered

Rechargeable batteries that can be implemented at the scale of the power grid are needed for widespread adoption of renewable energy. These batteries must be non-flammable and inexpensive because safety and cost are paramount concerns for large-scale battery installations. This CAREER project will conduct fundamental research on advanced battery materials that have the potential for greater energy density and cycle life, while operating in non-flammable water-based electrolytes. Among the possible grid-scale battery options, rechargeable Zn-MnO2 batteries are attractive because the basis materials are inexpensive, safe, and widely available. However, the reversibility of the MnO2 reaction requires the addition of Bi, sometimes paired with other transition metals such as Cu. However, the action of these additional metals at the molecular level is not known, and this knowledge is important to rationally engineer the material for optimal use. This project addresses this problem by using advanced characterization techniques to observe electrochemical interactions between MnO2 and the added metals in real time during battery cycling. The observed structure-function relationships will then be exploited to engineer the materials for improved batteries. An integrated education plan will develop materials and tools to train research students in effective scientific communication through the internet and blogging. This is because it would be transformational if every researcher had skills to communicate the importance of their work to the general public. Online materials will be produced about the importance of electrochemistry and energy storage, as well as online scientific educational materials for Boston area K-12 students.This project will examine electrochemical mechanisms in electrodes with MnO2 that has been doped with one or more metal cations. Previous work has demonstrated that during cycling Bi promotes formation of a layered birnessite form of MnO2 that is disordered or lacking in long-range structural periodicity. Determination of atomic positions in such a material requires techniques based on short-range order such as X-ray and Raman spectroscopy. In the case where MnO2 is dual doped with Bi and Cu, the three metal atoms (Mn, Bi, and Cu) are all electrochemically active during battery operation, meaning interactions such as electron mediator effects between the metals may be important, and this will be assessed. Work will begin with the synthesis of well-characterized, crystalline model compounds of doped MnO2, from which structural motifs can be established and atomic positions can be refined. Information from these model compounds will then be used to characterize dynamic atomic positions and interactions in electrodes during cycling, as observed by operando techniques in real-world disordered materials. To understand the electrode system as a whole, solubility of the dopants will be probed to account for transport of species via the electrolyte, and the impact of Zn cations on the MnO2 mechanism will be studied. The insights gained will aid development of rechargeable Zn-MnO2 batteries, and also contribute to understanding the electrochemistry of multiple redox-active sites in layered materials.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.

可再生能源的广泛采用需要能够在电网规模上实施的充电电池。这些电池必须不易燃且价格低廉，因为安全性和成本是大规模电池安装的首要考虑因素。该职业项目将对先进电池材料进行基础研究，这些材料具有更高的能量密度和循环寿命的潜力，同时在不可燃的水基电解质中运行。在可能的电网规模电池选择中，可充电锌锰电池很有吸引力，因为其基础材料便宜、安全且广泛可用。然而，MnO2 反应的可逆性需要添加 Bi，有时还需要与其他过渡金属（例如 Cu）配对。然而，这些附加金属在分子水平上的作用尚不清楚，这一知识对于合理设计材料以实现最佳使用非常重要。该项目通过使用先进的表征技术来解决这个问题，以在电池循环过程中实时观察 MnO2 和添加金属之间的电化学相互作用。然后将利用观察到的结构-功能关系来设计改进电池的材料。综合教育计划将开发材料和工具来培训研究生通过互联网和博客进行有效的科学交流。这是因为，如果每个研究人员都有能力向公众传达他们工作的重要性，这将是变革性的。将制作有关电化学和能量存储重要性的在线材料，以及为波士顿地区 K-12 学生提供的在线科学教育材料。该项目将研究掺杂一种或多种金属阳离子的 MnO2 电极的电化学机制。先前的研究表明，在循环过程中，Bi 会促进层状水钠锰矿形式 MnO2 的形成，这种层状水钠锰矿形式是无序的或缺乏长程结构周期性。确定此类材料中的原子位置需要基于短程有序的技术，例如 X 射线和拉曼光谱。在 MnO2 与 Bi 和 Cu 双重掺杂的情况下，三种金属原子（Mn、Bi 和 Cu）在电池运行期间均具有电化学活性，这意味着金属之间的电子介体效应等相互作用可能很重要，对此将进行评估。工作将从合成掺杂 MnO2 的良好表征的晶体模型化合物开始，从中可以建立结构图案并可以细化原子位置。来自这些模型化合物的信息将用于表征循环过程中电极中的动态原子位置和相互作用，正如通过操作技术在现实世界的无序材料中观察到的那样。为了从整体上了解电极系统，将探讨掺杂剂的溶解度以解释物质通过电解质的传输，并研究 Zn 阳离子对 MnO2 机制的影响。获得的见解将有助于可充电 Zn-MnO2 电池的开发，也有助于了解层状材料中多个氧化还原活性位点的电化学。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。