Figure 3: Fracture toughness measurement by nanoindentation.
From: High damage tolerance of electrochemically lithiated silicon
(a–c) SEM images of residual indents for a lithiated electrode of Li0.87Si, showing (a) no cracking, (b) radial cracking and (c) massive cracking subjected to different applied indentation loads (scale bar, 0.5 μm in a; 1 μm in b; 2 μm in c). (d–f) SEM images of residual indents for a lithiated Si electrode of Li1.56Si showing no cracking subjected to different applied indentation loads (scale bar, 1 μm in d and e; 2 μm in f). (g) The indentation loads (symbols) applied to the lithiated electrodes with different Li contents, corresponding to images in (a–f). The blue solid curve represents the upper load limit above which massive cracking occurred and the black solid curve the lower limit below which no crack was induced. The dashed lines show the qualitative trends interpolated from the data. (h) Fracture toughness and fracture energy of lithiated Si as a function of Li concentration.
