Fig. 5.

In situ TEM probing of the SnO₂ NP expansion in a graphene cage. a Schematic and captured in situ TEM images from time-lapse movies of b–h SnO₂@GC-21 (Supplementary Movie 1–3), i, j SnO₂@GC-0 (Supplementary Movie 4) and k, l SnO₂@GC-49 (Supplementary Movie 5). The lithiation process within graphene encapsulation is obviously interpreted by in situ TEM images. Graphene cage fracture occurred when aggregated SnO₂ NPs in SnO₂@GC-0 completely expanded, while the SnO₂@GC-21, 49 samples have enough space for lithium storage, especially the SnO₂@GC-21 whose void space is fully utilized by the expansion. Scale bars: b–d 50 nm; e, f 20 nm; g, h 2 nm; i, j 200 nm; k, l 100 nm