Alloying anode materials offer high capacity for next-generation batteries, but the performance of these materials often decays rapidly with cycling because of volume changes and associated mechanical degradation or fracture. The direct measurement of crystallographic strain evolution in individual particles has not been reported, however, and this level of insight is critical for designing mechanically resilient materials. Here, we use operando X-ray diffraction to investigate strain evolution in individual germanium microparticles during electrochemical reaction with lithium. The diffraction peak was observed to shift in position and diminish in intensity during reaction because of the disappearance of the crystalline Ge phase. The compressive strain along the [111] direction was found to increase monotonically to a value of −0.21%. This finding is in agreement with a mechanical model that considers expansion and plastic deformation during reaction. This new insight into the mechanics of large-volume-change transformations in alloying anodes is important for improving the durability of high-capacity batteries.

中文翻译：

---

Operando同步加速器测量锂电池中单个合金阳极颗粒中应变的演变

合金阳极材料可为下一代电池提供高容量，但由于体积变化以及相关的机械性能下降或破裂，这些材料的性能通常会随着循环而迅速衰减。但是，还没有直接测量单个颗粒中结晶应变演变的测量结果，而这种见识水平对于设计机械弹性材料至关重要。在这里，我们使用操作X射线衍射来研究在与锂的电化学反应过程中单个锗微粒中的应变演化。由于结晶的Ge相的消失，在反应过程中观察到衍射峰的位置移动并且强度减小。发现沿着[111]方向的压缩应变单调增加到-0.21％的值。这一发现与考虑反应过程中的膨胀和塑性变形的力学模型是一致的。对合金阳极中大体积变化转变机理的新见解对于提高高容量电池的耐用性非常重要。