Nelson Douglas Lars, Sandoval Stephanie E, Pyo Jaechan, Bistri Donald, Thomas Talia A, Cavallaro Kelsey Anne, Lewis John A, Iyer Abhinav S, Shevchenko Pavel, Di Leo Claudio V, McDowell Matthew T
School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
Daniel Guggenheim School of Aerospace Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
ACS Energy Lett. 2024 Nov 26;9(12):6085-6095. doi: 10.1021/acsenergylett.4c02800. eCollection 2024 Dec 13.
Solid-state batteries (SSBs) with silicon anodes could enable improved safety and energy density compared to lithium-ion batteries. However, degradation arising from the massive volumetric changes of silicon anodes during cycling is not well understood in solid-state systems. Here, we use X-ray computed microtomography to reveal micro- to macro-scale chemo-mechanical degradation processes of silicon anodes in SSBs. Mud-type channel cracks driven by biaxial tensile stress form across the electrode during delithiation. We also find detrimental cracks at the silicon/solid electrolyte interface that form due to local reaction competition between neighboring domains of different sizes. Continuum phase-field damage modeling quantifies stress-driven channel cracking and shows that the lithiated silicon stress state is critical for determining the extent of interfacial fracture. This work reveals the mechanisms that govern SSBs compared to conventional lithium-ion batteries and provides guidelines for engineering chemo-mechanically resilient electrodes for high-energy batteries.
与锂离子电池相比，采用硅阳极的固态电池（SSB）可提高安全性和能量密度。然而，在固态系统中，硅阳极在循环过程中因大量体积变化而导致的降解尚未得到充分理解。在此，我们使用X射线计算机显微断层扫描技术来揭示固态电池中硅阳极从微观到宏观尺度的化学机械降解过程。在脱锂过程中，由双轴拉应力驱动的泥状通道裂纹会贯穿整个电极。我们还发现在硅/固体电解质界面处存在有害裂纹，这些裂纹是由于不同尺寸的相邻区域之间的局部反应竞争而形成的。连续相场损伤模型量化了应力驱动的通道开裂，并表明锂化硅的应力状态对于确定界面断裂程度至关重要。这项工作揭示了与传统锂离子电池相比固态电池的运行机制，并为设计用于高能电池的化学机械弹性电极提供了指导。
