UNS: Dendrite-Free Storage of Lithium Metal in Porous Graphene Networks

主要研究者：Nikhil KoratkarProposal编号：1510828可充电锂离子电池通过存储风能和太阳能等可再生资源产生的电力，或为零排放电动汽车提供动力，支持可持续能源系统的发展。 锂离子电池的一个基本可靠性问题是在电池内形成锂金属晶须，最终使电池短路，产生潜在的火灾危险并缩短电池寿命。该项目的目标是开发一种锂离子电池电极，其中含有一种称为多孔石墨烯的碳，旨在抑制这种有害过程。 该项目将寻求对多孔石墨烯上锂金属形成的基本理解，然后利用这些信息设计更高性能，更安全的锂离子电池。 与该项目相关的教育活动包括开发用于工程课堂的锂离子电池的互动学习模块，以及向当地高中推广纳米技术主题。用于电化学能量存储的锂离子电池的基本问题是由于在阳极的外表面上电镀锂金属而最终形成锂金属枝晶，而不是在需要高能量密度存储的阳极内。 这些微观突起在重复循环时生长，并最终刺穿隔膜，接触阴极，并使装置短路。 拟议研究的总体目标是对微孔石墨烯阳极中的锂金属电镀和枝晶形成有基本的了解，然后利用这些信息开发微结构多孔石墨烯网络，以抑制枝晶形成并将锂金属电镀限制在多孔网络内。 为此，研究计划有四个目标。 第一个目标是了解石墨烯缺陷在吸引锂离子和启动电镀机制中的作用。 第二个目标是调节石墨烯中缺陷的类型和密度，以控制多孔石墨烯网络内的锂金属储存。 第三个目标是探索如何利用机械约束和电场调制效应来抑制多孔石墨烯结构中锂枝晶的形成。 最后，在目标4下，将表征锂离子通过多孔石墨烯结构扩散的动力学。 详细的从头算和分子动力学模拟，以及X射线光电子能谱（XPS），电化学阻抗谱（IES），SEM和TEM的组合，将用于实现这些目标的工具。 在这四个目标下获得的基本理解将用于制造具有微结构化多孔石墨烯阳极的锂离子电池，所述微结构化多孔石墨烯阳极被设计成抑制锂金属枝晶形成。 将通过能量密度、功率密度和充电/放电循环测量来评估性能。 研究结果将用于开发一个交互式虚拟实验室，用于设计基于石墨烯的锂离子可充电电池电极结构，用于本科机械系统实验室课程。

PI: Nikhil KoratkarProposal Number: 1510828Rechargeable lithium ion batteries support the development of sustainable energy systems by storing electricity generated by renewable resources such as wind and solar energy, or by powering zero-emission electric vehicles charged by electricity from renewable resources. A fundamental reliability issue with lithium ion batteries is the formation of lithium metal whiskers within the battery that ultimately short out the battery, creating a potential fire hazard and reducing battery life. The goal of this project is develop a lithium ion battery electrode which contains a form of carbon called porous graphene that will be designed to suppress this detrimental process. The project will seek fundamental understanding of lithium metal formation on the porous graphene and then use this information to design a higher performance, and safer, lithium ion battery. The educational activities associated with this project include the development of interactive learning module on lithium ion batteries for engineering classroom use, and outreach on nanotechnology topics to local high schools.A fundamental problem with lithium ion batteries for electrochemical energy storage is the eventual formation of lithium metal dendrites resulting from the plating of lithium metal on the outside surface of the anode, as opposed to within the anode where it is needed for high-energy density storage. These microscopic projections grow upon repeated cycling and ultimately pierce the separator, touch the cathode, and short out the device. The overall goals of the proposed research are to develop a fundamental understanding of lithium metal plating and dendrite formation in microporous graphene anodes, and then to use this information to develop micro-structured porous graphene networks that suppress dendrite formation and confine lithium metal plating within the porous network. Towards this end, the research plan has four objectives. The first objective is to understand the role of graphene defects in attracting lithium ions and initiating the plating mechanism. The second objective is to tune the type and density of defects in graphene in order control lithium metal storage within porous graphene networks. The third objective is to explore how mechanical confinement and electric field modulation effects can be used to suppress the formation of lithium dendrites in porous graphene structures. Finally, under objective 4, the kinetics of lithium ion diffusion though porous graphene structures will be characterized. A combination of detailed Ab initio and molecular dynamics simulations, as well as X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (IES), SEM, and TEM, will be the tools used carry out these objectives. Fundamental understanding obtained under these four objectives will be used to fabricate a lithium ion battery with microstructured porous graphene anodes designed to suppress lithium metal dendrite formation. Performance will be assessed through energy density, power density and charge/discharge cycling measurements. The research results will be used to develop an interactive virtual laboratory on the design of graphene based electrode structures for Li-ion rechargeable batteries for use in an undergraduate mechanical systems laboratory course.