Microscopic insights into glassy solid electrolytes

玻璃态固体电解质的微观观察

• 批准号: 2746781
• 金额: --
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2746781
• 关键词: Microscopic; insights; into; glassy; solid

Recently the scientific community, with significant contribution from the SOLBAT project, has made great progress in understanding the origins of metallic lithium "dendrite" formation and propagation in solid electrolytes [Ning et al. 2021]. All evidence points toward the detrimental role of reactive interphases at the Li-SSE electrolyte interface [McDowell et al. 2019] and the grain boundaries in crystalline solids [Sakamoto et al. 2017]. Glassy (non-crystalline) solid-state electrolytes (SE) have attracted much attention due to advantages over their crystalline counterparts: isotropic ionic conduction, large available composition scales, thermal history manipulations, weak electronic contribution to the conductivity, ease of fabrication into films and, most importantly, absence of grain-boundaries and associated resistance.Some of the most promising SEs have glass or glass-ceramic microstructures, including LiPON [Dudney et. al. 2018] and thiophosphates [Wang et al. 2021]. Nevertheless, the interplay between atomic structure, microstructure, ionic and electronic conductivity, and electro-chemo-mechanical properties of the Li|SE interphase remains elusive. Therefore, the scientific community is still struggling to design SEs with high Li-ion conductivity, able to prevent dendrite formation at commercially relevant current densities and processable as thin film at scale.In this project, the student will combine advanced experiments and machine-learning-driven simulations to explore the synthesis and characterization properties (structural, physico-chemical, electrochemical and mechanical) of solid glass electrolytes. Oxy-halide glasses will be used as a model system because of their promising ionic conductivity and compositional tunability [Goodenough et al. 2016, Lunz et al. 2019]. In the first part, structure and mechanism of ion conduction in the bulk electrolyte will be explored experimentally (X-ray PDF, solid-state NMR and impedance spectroscopy) and computationally, using ML-based methodology. In the second part, leveraging existing expertise in XPS, AFM and advanced electron microscopy characterisation (including cryo-FIB cross sectioning and low-dose TEM), the Li-SE interphase will be probed. Combining these experiments with ML-driven simulations on the ten-nanometre length scale, the project promises new insight into the effect of composition and morphology on mechanical properties and ion transport.The Pasta group has recently investigated the effect of crystal structure and microstructure on ionic conduction in Li2OHX (X=Cl, Br) solid electrolytes and has developed a unique expertise in melting-solidification processes to control grain size [Pasta et. al. 2021]. Rapid quenching of the molten salt will produce glasses that will then be characterized structurally (X-ray PDF in collaboration with Dr. Maria Diaz-Lopez, beamline scientist at Diamond Light Source), mechanically, and electrochemically. The Deringer group specialises in the development and application of machine-learning-based force fields for simulations of structurally complex materials [Deringer et al. 2021].The combined experimental-computational approach will be first validated on a well-defined model system, viz. lithium halide antiperovskites (for which the melt-quenching can be directly described with established simulation protocols) - but the more ambitious long-term aim is for computation to support and accelerate the material selection and processing conditions workflows more generally, ultimately leading to a combined approach for the discovery of glassy solid-state electrolytes.This is a 4-year Faraday Institution Studentship (part of the course fee paid from Oxford Materials funds)

最近，科学界在 SOLBAT 项目的重大贡献下，在理解固体电解质中金属锂“枝晶”形成和传播的起源方面取得了巨大进展。 2021]。所有证据都表明 Li-SSE 电解质界面上反应性中间相的有害作用 [McDowell 等人，2017]。 2019]和结晶固体中的晶界[Sakamoto等人。 2017]。玻璃态（非晶态）固态电解质（SE）因其相对于晶态电解质的优势而备受关注：各向同性离子传导、大的可用成分尺度、热历史操纵、电子对电导率的贡献较弱、易于制造成薄膜，最重要的是，没有晶界和相关的电阻。一些最有前途的SE具有玻璃或 玻璃陶瓷微结构，包括 LiPON [Dudney 等人。等人。 2018]和硫代磷酸盐[Wang等人。 2021]。然而，Li|SE 界面的原子结构、微观结构、离子和电子电导率以及电化学机械性能之间的相互作用仍然难以捉摸。因此，科学界仍在努力设计具有高锂离子电导率的SE，能够在商业相关的电流密度下防止枝晶形成，并可大规模加工成薄膜。在这个项目中，学生将结合先进的实验和机器学习驱动的模拟来探索固体玻璃电解质的合成和表征特性（结构、物理化学、电化学和机械）。卤氧化物玻璃将被用作模型系统，因为它们具有良好的离子电导率和成分可调性[Goodenough 等人，2017]。 2016，伦茨等人。 2019]。在第一部分中，将使用基于机器学习的方法通过实验（X 射线 PDF、固态 NMR 和阻抗谱）和计算方式探索本体电解质中离子传导的结构和机制。在第二部分中，将利用 XPS、AFM 和先进电子显微镜表征（包括冷冻 FIB 横截面和低剂量 TEM）方面的现有专业知识，对 Li-SE 界面进行探测。将这些实验与 10 纳米长度尺度的 ML 驱动模拟相结合，该项目有望对成分和形态对机械性能和离子传输的影响产生新的见解。Pasta 小组最近研究了晶体结构和微观结构对 Li2OHX（X=Cl，Br）固体电解质中离子传导的影响，并在控制晶粒尺寸的熔融-凝固过程方面开发了独特的专业知识 [Pasta et.等人。 2021]。熔盐的快速淬火将产生玻璃，然后对玻璃进行结构表征（X 射线 PDF 与 Diamond Light Source 光束线科学家 Maria Diaz-Lopez 博士合作）、机械和电化学表征。 Deringer 小组专门从事基于机器学习的力场的开发和应用，以模拟结构复杂的材料 [Deringer 等人，2017]。 2021]。实验-计算相结合的方法将首先在定义明确的模型系统上进行验证，即。卤化锂反钙钛矿（可以使用已建立的模拟协议直接描述熔融淬火） - 但更雄心勃勃的长期目标是通过计算来支持和加速更广泛的材料选择和加工条件工作流程，最终形成用于发现玻璃态固态电解质的组合方法。这是一个为期 4 年的法拉第机构学生奖学金（部分课程费用由牛津材料基金支付）