Collaborative Research: Investigation of the Relationship between Processing Conditions and Morphology of Lithium During Electroplating

石墨目前被用作大多数可充电锂离子电池的阳极成分。用锂金属取代石墨有望将电池容量提高数倍，同时降低成本。在电池充放电过程中，锂金属表面容易失去其光滑的形态，并形成许多尖锐的突起，这种现象称为枝晶生长。枝晶生长导致较差的电池寿命并引起严重的安全问题，这两者都是锂金属基可充电电池商业化的主要障碍。该项目旨在提供基础知识，以指导具有长循环寿命和稳定性的锂金属阳极的先进制造。它将侧重于了解电池循环过程中锂金属内积累的残余应力在触发锂枝晶生长中的作用，以及如何通过设计新型多孔阳极结构来消除其不利影响。为实现这一目标，将开展综合表征、建模和制造活动。除了对电动汽车和电网的下一代电池的开发产生重大影响外，该项目中获得的机械理解还将促进在储能设备中使用其他地球丰富的金属材料。该项目的综合教育和外展部分将使广泛的群体受益，为美国原住民和社区大学学生提供真实的研究经验，通过积极的学生招聘和保留促进本科生研究和研究生教育，并将电池研究的最新进展纳入力学和材料科学课程。还没有建立对锂枝晶生长机理的完全理解。该项目建立在PI最近的发现基础上，将研究应力作为电镀过程中控制锂表面形态的关键工艺条件，这在以前很少受到关注。它将结合联合收割机原位和非原位表征、建模和制造研究，以：1）了解应力、电流密度和电镀时间如何共同控制锂形态; 2）构建锂形态图以预测作为可控处理条件的函数的锂电镀形态，3）应用所获得的知识来设计能够在高电流密度下稳定循环的锂阳极结构，和4）探索潜在的成本竞争性方法以制造高性能锂阳极。这项研究有望为高容量可充电电池的稳定锂金属阳极结构的制造提供重要的科学指导。该奖项反映了NSF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。

Graphite is currently used as the anode component in most rechargeable lithium-ion batteries. Replacing graphite with lithium metal holds the promise to improve the battery capacity by several times while also reducing costs. During battery charging and discharging, the lithium metal surface is prone to losing its smooth morphology and forms many sharp protrusions, a phenomenon, known as dendrite growth. Dendrite growth results in inferior battery life and induces severe safety concerns, both of which are major barriers to the commercialization of lithium-metal-based rechargeable batteries. This project aims to provide fundamental knowledge to guide the advanced manufacturing of lithium metal anodes with long cycle life and stability. It will focus on understanding the role of residual stress that accumulates within lithium metal during battery cycling in triggering lithium dendrite growth, and how its adverse effect can be eliminated by the design of a novel porous anode architecture. Integrated characterization, modeling and manufacturing activities will be carried out to achieve this goal. In addition to having major impacts on the development of next-generation batteries for electrical vehicles and electric grids, the mechanistic understanding acquired in the project will also facilitate the use of other earth-abundant metallic materials in energy storage devices. The integrated education and outreach component of the project will benefit a broad range of groups by providing authentic research experiences to native Americans and community college students, promoting undergraduate research and graduate education through active student recruitment and retention, and integrating the latest progress in battery research into curriculum on mechanics and materials science.Despite extensive efforts, a complete understanding of the lithium dendrite growth mechanism has not yet been established. This project builds on the PIs' recent findings and will investigate stress as a key processing condition for controlling lithium surface morphology during electroplating, which has previously received little attention. It will combine in-situ and ex-situ characterizations, modeling and fabrication studies to: 1) understand how the stress, current density and plating time collectively control the lithium morphology; 2) construct a lithium morphology diagram to predict lithium plating morphology as a function of controllable processing conditions, 3) apply the acquired knowledge to design lithium anode architecture that enables stable cycling under high current densities, and 4) explore a potential cost-competitive method to manufacture high-performance lithium anodes. This research is expected to provide essential scientific guidance for the manufacturing of stable lithium metal anode structures for high capacity rechargeable batteries.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.