Thin film electrolytes for novel lithium-ion battery designs

牛津大学是法拉第研究所(https://faraday.ac.uk)，)的创始成员之一，法拉第研究所是英国新的电池科学和技术旗舰项目。可充电锂离子电池以其高能量密度和高效率给便携式电子行业带来了革命性的变化，现在被广泛部署在电动汽车中。然而，它们存在严重的安全和可靠性问题，其中许多问题与易燃液体电解液的使用有关。世界各地都在竞相设计和制造固态电解质材料，以解决其中的一些问题。一系列氧化物、磷酸盐和硫化物化合物的导电率比液体电解液低得多，但如果电解液的厚度能够减少，则有望在全固态电池原型设计中使用。电极和电解液之间的界面也是众所周知的电化学不稳定的，改变界面性质的策略正在被广泛探索。本项目将使用脉冲激光沉积技术来沉积薄膜，以改变电极和电解液材料之间的界面化学，以提高原型固态电池设计的循环性能。尽管薄膜中间层在世界各地的实验室中吸引了大量关注，但大多数报道的工作都是非常经验性的-“我们添加一层XXX，循环性能就会提高”。该项目将采用的研究方法的新颖性在于，采用了聚焦材料科学的方法来准确识别和控制沉积的内容，然后表征循环后的界面区域，以了解发生的化学和形态变化。该项目的第一阶段将利用X射线衍射和电子显微镜技术研究沉积参数对薄膜的物相、微结构和力学性能的影响，以确定最佳的生长条件，并将测量有希望的结构的电化学性能。可提供用于生长完整薄膜电池的设备(由法拉第研究所和罗伊斯研究所提供资金)。在项目的第二阶段，选择了更先进的电子显微镜技术和基于操作中同步加速器的工具(XPS/XAS/X射线衍射仪)的组合，以确定界面区域对电流转移的响应。通过这种方式，我们将建立对界面层如何影响薄膜电池结构的电化学性能的机理理解，并能够提出优化性能的方法。该项目属于EPSRC能源储存研究领域。

Oxford University is one of the founder members of the Faraday Institution (https://faraday.ac.uk), the UK's new flagship programme for battery science and technology. Rechargeable lithium-ion batteries have revolutionized the portable electronics industry because of their high energy density and efficiency, and are now widely deployed in electric vehicles. However, they suffer from significant safety and reliability issues, many of which are related to the use of flammable liquid electrolytes. There is a world-wide race to design and manufacture solid-state electrolyte materials that could resolve some of these problems. A range of oxide, phosphate and sulphide compounds have rather lower conductivities than liquid electrolytes, but show promise for use in prototype all solid-state battery designs if the thickness of the electrolyte can be reduced. The interfaces between electrodes and electrolytes are also well known to be electrochemically unstable, and strategies to modify the interfacial properties are being widely explored.This project will use pulsed laser deposition techniques to deposit thin films that modify the chemistry of the interfaces between electrode and electrolyte materials in order to improve the cycling performance of prototype solid state battery designs. While thin film interlayers are attracting a lot of attention In laboratories worldwide, most of the reported work is very empirical - "we add a layer of XXX and the cycling performance improves". The novelty of the research methodology that will be applied in this project lies in the focussed material science approach to identify and control exactly what is being deposited and then to characterise the interfacial regions after cycling to understand the chemical and morphological changes that occur. The first stage of the project will study the influence of the deposition parameters on the phase, microstructure and mechanical properties of the films using XRD and electron microscopy techniques to establish the optimised growth conditions, and the electrochemical performance of promising structures will be measured. Facilities for the growth of complete thin film cells are available (funded by the Faraday Institution and Royce Institute). In the second stage of the project, a combination of more advanced electron microscopy techniques and in-operando synchrotron based tools (XPS/XAS/XRD) have been selected in order to determine the response of the interfacial region to current transfer. In this way we will build up a mechanistic understanding of how interfacial layers can influence the electrochemical performance of thin film battery structures, and be able to propose methods for optimising properties. This project falls within the EPSRC research area of Energy Storage.