Li Shaowen, Chai Zhigang, Wang Zhaohui, Tai Cheuk-Wai, Zhu Jiefang, Edström Kristina, Ma Yue
State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an, 710072, China.
Ångström Advanced Battery Centre (ÅABC), Department of Chemistry-Ångström Laboratory, Uppsala University, SE-75121, Uppsala, Sweden.
Adv Mater. 2023 Nov;35(47):e2306826. doi: 10.1002/adma.202306826. Epub 2023 Oct 15.
Li-containing alloys and metallic deposits offer substantial Li storage capacities as alternative anodes to commercial graphite. However, the thermodynamically in sequence, yet kinetically competitive mechanism between Li solubility in the solid solution and intermediate alloy-induced Li deposition remains debated, particularly across the multiple scales. The elucidation of the mechanism is rather challenging due to the dynamic alloy evolution upon the non-equilibrium, transient lithiation processes under coupled physical fields. Here, influential factors governing Li solubility in the Li-Zn alloy are comprehensively investigated as a demonstrative model, spanning from the bulk electrolyte solution to the ion diffusion within the electrode. Through real-time phase tracking and spatial distribution analysis of intermediate alloy/Li metallic species at varied temperatures, current densities and particle sizes, the driving force of Li solubility and metallic plating along the Li migration pathway are probed in-depth. This study investigates the correlation between kinetics (pronounced concentration polarization, miscibility gap in lattice grains) and rate-limiting interfacial charge transfer thermodynamics in dedicating the Li diffusion into the solid solution. Additionally, the lithiophilic alloy sites with the balanced diffusion barrier and Li adsorption energy are explored to favor the homogeneous metal plating, which provides new insights for the rational innovation of high-capacity alloy/metallic anodes.
含锂合金和金属沉积物作为商业石墨的替代阳极，具有可观的锂存储容量。然而，锂在固溶体中的溶解度与中间合金诱导的锂沉积之间的热力学顺序但动力学竞争机制仍存在争议，尤其是在多个尺度上。由于在耦合物理场下非平衡、瞬态锂化过程中合金的动态演变，阐明该机制颇具挑战性。在此，作为一个示范模型，全面研究了影响锂在锂锌合金中溶解度的因素，范围从本体电解质溶液到电极内的离子扩散。通过在不同温度、电流密度和颗粒尺寸下对中间合金/锂金属物种进行实时相跟踪和空间分布分析，深入探究了沿锂迁移路径的锂溶解度和金属镀层的驱动力。本研究在致力于锂扩散到固溶体的过程中，研究了动力学（明显的浓度极化、晶格晶粒中的混溶间隙）与限速界面电荷转移热力学之间的相关性。此外，还探索了具有平衡扩散势垒和锂吸附能的亲锂合金位点，以利于均匀的金属镀层，这为高容量合金/金属阳极的合理创新提供了新的见解。
