Figure 3
(a) Schematic showing the configuration for in situ TEM observation of the lithiation process. A NiCo2S4 nanosheet was placed on a Cu wire, serving as the working electrode; the counter-electrode consisted of a small piece of Li metal coated with Li2O (solid electrolyte) on the tip of a W wire. A bias voltage of −3 V was applied between the two electrodes to drive the lithiation process. (b–d) TEM images monitoring the lithiation process of NiCo2S4 nanosheet at time equal to 0, 0.5 and 20 min, respectively. The insets in b and d show the corresponding SAED patterns of the NiCo2S4 nanosheet. SAED, selected area electron diffraction; TEM, transmission electron microscopy.
