Fig. 3

Series of cross-sectional SEM images of electrode thickness differences before and after 100 cycles with FEM of GS and MGS upon lithiation. a–f Cross-sectional views of G, GS, and MGS electrodes before cycling (a–c) and after 100 cycles (d–f), respectively. Finite element model for GS (g) and MGS (i), where photographs show each particle. Diffusion-induced hoop stress in lithiation state (h, j). The red dotted line indicates the diagonal path. k Comparison of hoop stress along with diagonal path. l Representative volume increase versus lithiation state. Inset: Expansion ratio depending on different pore types. Scale bars, 50 μm (a–f) and 5 μm (g, i)