Hua Weicheng, Nylund Inger-Emma, Cova Federico, Svensson Ann Mari, Blanco Maria Valeria
Department of Materials Science and Engineering, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
BL31 FaXToR Beamline, CELLS- ALBA Synchrotron Light Source, 08290 Cerdanyola del Vallès, Barcelona Spain.
Sci Rep. 2023 Nov 22;13(1):20447. doi: 10.1038/s41598-023-47355-7.
[Formula: see text] is a promising material for developing high-capacity anodes for lithium-ion batteries (LIBs). However, microstructural changes of [Formula: see text] anodes at the particle and electrode level upon prolonged cycling remains unclear. In this work, the causes leading to capacity fade on [Formula: see text] anodes were investigated and simple strategies to attenuate anode degradation were explored. Nanostructured [Formula: see text] from diatomaceous earth was integrated into anodes containing different quantities of conductive carbon in the form of either a conductive additive or a nanometric coating layer. Galvanostatic cycling was conducted for 200 cycles and distinctive trends on capacity fade were identified. A thorough analysis of the anodes at selected cycle numbers was performed using a toolset of characterization techniques, including electrochemical impedance spectroscopy, FIB-SEM cross-sectional analysis and TEM inspections. Significant fragmentation of [Formula: see text] particles surface and formation of filigree structures upon cycling are reported for the first time. Morphological changes are accompanied by an increase in impedance and a loss of electroactive surface area. Carbon-coating is found to restrict particle fracture and to increase capacity retention to 66%, compared to 47% for uncoated samples after 200 cycles. Results provide valuable insights to improve cycling stability of [Formula: see text] anodes for next-generation LIBs.
[化学式：见原文]是开发用于锂离子电池（LIBs）的高容量阳极的一种有前景的材料。然而，[化学式：见原文]阳极在长时间循环过程中在颗粒和电极层面的微观结构变化仍不清楚。在这项工作中，研究了导致[化学式：见原文]阳极容量衰减的原因，并探索了减轻阳极降解的简单策略。将来自硅藻土的纳米结构[化学式：见原文]以导电添加剂或纳米涂层的形式整合到含有不同数量导电碳的阳极中。进行了200次恒电流循环，并确定了容量衰减的独特趋势。使用包括电化学阻抗谱、聚焦离子束扫描电子显微镜（FIB-SEM）横截面分析和透射电子显微镜（TEM）检查在内的一系列表征技术工具，对选定循环次数的阳极进行了全面分析。首次报道了[化学式：见原文]颗粒表面在循环过程中的显著破碎以及细丝状结构的形成。形态变化伴随着阻抗增加和电活性表面积损失。发现碳涂层可限制颗粒破裂，并将容量保持率提高到66%，相比之下，未涂层样品在200次循环后的容量保持率为47%。研究结果为提高下一代LIBs中[化学式：见原文]阳极的循环稳定性提供了有价值的见解。
