Solid glass electrolytes for Li-metal batteries

传统锂离子电池的化学性质正接近其物理化学极限。为了开发高能量密度、低成本和安全的电池，需要采用高能量活性材料，以满足不断扩大的电动汽车市场的要求，并为电动飞行等新应用提供动力。这可以通过用固体电解质取代有机液体电解质来实现，从而实现锂金属阳极的安全实施。固体玻璃电解质之所以受到广泛关注，主要是因为它们比晶体电解质具有各向同性离子传导、没有晶界和相关电阻以及易于制成薄膜等优点。此外，由于非晶玻璃的开放结构，其离子电导率通常高于晶体玻璃。锂离子导电玻璃可分为两大类：氧化物和硫化物。氧化玻璃电解质具有化学稳定性，并显示出广泛的电化学稳定性窗口，但其锂离子在室温下的电导率太低，无法用于高能电池（10E-6-10E-8 S/cm）。另一方面，由于硫化物离子的高极化率，硫化物玻璃在室温下显示出高锂离子电导率（10E-3 - 10E-5 S/cm）。不幸的是，它们会与周围的湿气发生反应，产生有毒的硫化氢气体。由抗钙钛矿羟基卤化锂（Li2OHX， X=Cl, Br）衍生的卤化氧玻璃电解质最近显示出弥合氧化物电化学稳定性和硫化物离子电导率之间差距的潜力。在这个项目中，学生将探索与锂金属阳极相容的氧卤化物固体玻璃电解质的合成和表征（结构，物理化学和电化学）。我们将详细研究其组成和形貌对力学性能和离子输运的影响。离子传导的机制将通过实验（固态核磁共振和电化学阻抗谱）和第一性原理计算来探索。锂金属-固体电解质界面将通过XPS（非原位、原位和operando）、AFM和先进的电子显微镜技术进行探测。该项目属于EPSRC能源研究领域。这个主题的目的是为了让英国实现其环境和能源目标。该项目由部分赞助（DTP-CASE），并将与摩根先进材料公司合作开展。

The conventional Li-ion battery chemistry is approaching its physicochemical limit. High energy active materials need to be implemented to develop the high energy density, low-cost and safe batteries that can meet the requirements of the expanding electric vehicle market and empower novel applications such as electric flight. This could be achieved by replacing the organic liquid electrolyte with a solid electrolyte, enabling the safe implementation of Li-metal anodes.Solid glassy electrolytes have attracted much attention mainly due to their advantages over the crystalline counterparts, namely isotropic ionic conduction, absence of grain-boundaries and associated resistance and ease of fabrication into films. In addition, the ion conductivity of amorphous glasses is generally higher than that of their crystalline counterparts because of their open structure.Li-ion conducting glasses can be divided into two main categories: oxides and sulfides. Oxide glassy electrolytes are chemically stable and display a wide electrochemical stability window nevertheless their lithium-ion conductivity at room temperature is too low to be practical for high energy batteries (10E-6-10E-8 S/cm). Sulphide glasses, on the other hand, display high lithium-ion conductivities at room temperature (10E-3 - 10E-5 S/cm) thanks to the high polarisability of sulphide ions. Unfortunately, they can react with ambient moisture and generate the toxic hydrogen sulphide gas.Oxy-halide glassy electrolytes derived from anti-perovskite lithium hydroxy halides (Li2OHX, X=Cl, Br) have recently shown potential in bridging the gap between the electrochemical stability of oxides and ionic conductivity of sulphides.In this project the student will explore the synthesis and characterization (structural, physico-chemical and electrochemical) of oxy-halide solid glassy electrolytes, compatible with the lithium metal anode. The effect of composition and morphology on mechanical properties and ion transport will be investigated in detail. The mechanism of ion conduction will be explored both experimentally (solid-state NMR and electrochemical impedance spectroscopy) and by first-principle calculations. The lithium metal-solid electrolyte interphase will be probed by XPS (ex-situ, in-situ and operando), AFM and advanced electron microscopy techniques.This project falls within the EPSRC Energy research area. The aim of this theme is for the UK to meet its environmental and energy targets.The project is partially sponsored (DTP-CASE) and will be carried out in collaboration with Morgan Advanced Materials.