Electrochemical and microstructural analysis of the processes occurring in Si microwire-array anodes (and full-cells) for high capacity Lithium ion batteries

第一阶段提案中描述的主要目标是：为目前存在的锂离子电池制造最先进的硅线阳极（SWA），即使具有更高的容量和更高的可靠性，通过更好地了解锂化/脱锂过程中发生的基本过程，更可靠。尽管这是一个具有挑战性的目标，但它在很大程度上已经实现，因此在这里提出的继续研究中，目标将向前推进，主要是深入了解性能极限下的特性和先进的全电池性能。在整个第一阶段，大小对（峰值）电位的依赖性得到了理解。利用FFT阻抗谱，可以理解导线的不同长度和厚度如何影响阳极内的电荷转移和弹性相互作用。伏安法测量表明，当使用不同的金属丝几何形状时，扩散是如何受到限制的。这些包仍计划在第三年，以估计性能限制下的性能变化，如温度影响和不同的循环参数。在接下来的第三年中，应通过透射电子显微镜（TEM）研究这种结构变化。一种简单可靠的方法转移湿敏锂硅是成功的，可能会提高电子显微镜在湿度和光束敏感样品领域的科学相关性。除了继续最初提案中计划的工作包外，我们还引入了一个额外的工作包（WP 9），用于处理潜在阴极材料的TEM分析。

The main goal described in the first period proposal was: To build the most advanced silicon wire anode (SWA) for Li ion batteries presently existing even with higher capacities and higher reliability, more reliable by obtaining a better understanding of the basic processes occurring during lithiation / delithiation. Even though this is a challenging goal, it could be already fulfilled for the most part, so that in the here proposed continuation the goal will be pushed forward, mainly towards in depth understanding of the properties at performance limits and advanced full cell performance. Throughout the first period, the size dependency on the (peak) potential was understood. With FFT-Impedance Spectroscopy it could be understood how the different lengths and the thicknesses of the wires influence the charge transfer and the elastic interaction within the anode. Voltammetric measurements showed how the diffusion is limited when using different wire geometries. Those packages are still scheduled in the third year to estimate the property change at performance limits like temperature influence and different cycling parameters. This resulting structural change should be investigated by transmission electron microscopy (TEM) in the following third year. A simple and reliable method for the transfer of moisture sensitive Li-Si was successful and might boost the scientific relevance of electron microscopy in the field of moisture and beam sensitive samples. Besides the continuation of the work packages as planed in the initial proposal, we introduced an additional work package (WP 9) dealing with TEM analyses on potential cathode materials.