Lithium-ion batteries are yet to realize their full promise because of challenges in the design and construction of electrode architectures that allow for their entire interior volumes to be reversibly accessible for ion storage. Electrodes constructed from the same material and with the same specifications, which differ only in terms of dimensions and geometries of the constituent particles, can show surprising differences in polarization, stress accumulation and capacity fade. Here, using operando synchrotron X-ray diffraction and energy dispersive X-ray diffraction (EDXRD), we probe the mechanistic origins of the remarkable particle geometry-dependent modification of lithiation-induced phase transformations in V₂O₅ as a model phase-transforming cathode. A pronounced modulation of phase coexistence regimes is observed as a function of particle geometry. Specifically, a metastable phase is stabilized for nanometre-sized spherical V₂O₅ particles, to circumvent the formation of large misfit strains. Spatially resolved EDXRD measurements demonstrate that particle geometries strongly modify the tortuosity of the porous cathode architecture. Greater ion-transport limitations in electrode architectures comprising micrometre-sized platelets result in considerable lithiation heterogeneities across the thickness of the electrode. These insights establish particle geometry-dependent modification of metastable phase regimes and electrode tortuosity as key design principles for realizing the promise of intercalation cathodes.

由于电极结构的设计和构造存在挑战，锂离子电池尚未实现其全部承诺，电极结构允许其整个内部体积可逆地用于离子存储。由相同材料和相同规格构成的电极（仅在组成颗粒的尺寸和几何形状方面有所不同）在极化、应力累积和容量衰减方面可能表现出惊人的差异。在这里，我们使用操作同步加速器 X 射线衍射和能量色散 X 射线衍射 (EDXRD)，探讨了在 V ₂ O _{5中锂化诱导的相变的显着粒子几何依赖性修饰的机理起源}作为模型相变阴极。作为粒子几何形状的函数，观察到相共存状态的显着调制。具体来说，对于纳米尺寸的球形 V ₂ O _{5来说，亚稳相是稳定的}颗粒，以避免形成大的错配应变。空间分辨的 EDXRD 测量表明，粒子几何形状强烈改变了多孔阴极结构的曲折度。包含微米大小的片晶的电极结构中更大的离子传输限制导致电极厚度上相当大的锂化异质性。这些见解确立了亚稳态相态和电极弯曲度的粒子几何相关修改，作为实现插层阴极前景的关键设计原则。