Interfacial characterization of hybrid solid-liquid electrolytes for Li-metal anode batteries

锂金属的成功实施需要满足未来便携式电子产品和电动汽车的体积和重量能量密度要求。SOLBAT项目在理解锂金属上枝晶形成和扩展的原因方面取得了很好的进展|SE接口。在阴极处，在充电/放电期间活性颗粒的体积变化使得在SE内保持紧密接触成为一个显著的问题。目前，没有一种确定的SE候选物具有电化学稳定性、离子电导率和机械性能的必要组合来解决这个问题。其中固体保护的阳极与常规的液体填充的多孔阴极组合的混合固液电解质（HSE）电池将代表金属阳极电池的实际实施的更容易实施的途径。一个HE，介绍了一种新的固/液界面，在文献中研究很少，但往往与高阻抗。在这个项目中，学生将研究固体电解质-液体电解质界面作为一个功能的充电状态，循环，电流密度，温度和压力，使用一系列技术，包括电化学阻抗谱（3和4电极）、拉曼、AFM、XPS、通过FIB/等离子体-SEM的形态学研究、样品减薄和TEM-EDX以及接触角测量。我们将优先考虑与锂金属接触时具有稳定性的固体电解质，即石榴石LLZO，并探索掺杂，粒度和表面粗糙度/形态对界面阻抗的影响。利用XRD、SEM、EDX和EBSD、XPS、AFM和SEM辅助纳米压痕等表征方法，分析电池条件下电镀锂的微观结构，并将其与所得循环/失效行为联系起来，特别关注机械性能。了解随着电化学条件的变化，微观结构的变化，以及由此产生的性能变化。EPSRC研究领域主题：能源

A successful implementation of lithium metal is required to meet the volumetric and gravimetric energy density requirements of portable electronics and electric vehicles of the future. The SOLBAT project has made a good progress in understanding the causes of dendrite formation and propagation at the Li-metal|SE interface. At the cathode, volume changes of active particles during charge/discharge make retention of intimate contact within the SE a significant problem. Currently, none of the identified SE candidates have the necessary combination of electrochemical stability, ionic conductivity and mechanical properties to address this issue. A hybrid solid-liquid electrolyte (HSE) cell in which a solid-protected anode is combined with a conventional liquid-filled porous cathode would represent a more readily implementable route to the practical implementation of metal anode batteries. A HE, introduces a new solid/liquid interface, poorly investigated in the literature but often associated with high impedances.In this project, the student will investigate the solid electrolyte-liquid electrolyte interface as a function of charge state, cycling, current density, temperature and pressure, using a range of techniques including electrochemical impedance spectroscopy (3 and 4 electrodes), Raman, AFM, XPS, morphology studies by FIB/plasma-SEM, sample thinning and TEM-EDX and contact angle measurements. We will prioritize solid-electrolytes with proven stability in contact with Li-metal, i.e. Garnet LLZO and explore the effect of doping, grain size and surface roughness/morphology on the interfacial impedance. Strategies to mitigate high impedances, e.g. surface treatments and coatings will be investigated.Utilise characterisation methods including XRD, SEM with EDX and EBSD, XPS, AFM and SEM assisted nanoindentation to characterise the microstructure of electroplated lithium in cell conditions and tie this to the resultant cycling/failure behaviour, with particular focus on the mechanical properties. Establish an understanding of the changes in microstructure with changing electrochemical conditions, and the resultant changes in performance.EPSRC research area Theme: Energy