Sb-based alloy, such as Zn-Sb 1-3 , are promising anode materials because of their high theoretical capacities and suitable operating voltages. However, there have been very few studies on the detailed dynamical process of the phase transition during lithiation in the Sb-based intermetallic compounds, especially at atomic scale. By employing in-situ (scanning) transmission electron microscopy 4 , we studied the lithium-ion diffusion and multistep phase transition during the electrochemical

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... ation of individual single-crystal Zn 4 Sb 3 nanowires with atomic-resolution. Continuous phase transition from crystalline rhombohedral Zn 4 Sb 3 to hexagonal LiZnSb and then to cubic Li 2 ZnSb phases has been directly monitored upon successive lithium-ion intercalation, which is mediated by the formation of amorphous Li x Zn 4 Sb 3 at the early stage of lithiation. The kinetics of lithiation has been found to be highly anisotropic and relevant to the dynamics of the interfacial structures of the reaction front at different stages of lithiation.