1D to 3D hierarchical iron selenide hollow nanocubes assembled from FeSe2@C core-shell nanorods for advanced sodium ion batteries

3D hierarchical hollow nanocubes constructed by 1D FeSe2@C core-shell nanorods were successfully prepared by a thermally-induced selenization process of their Prussian blue microcubes precursor. Such novel nanorods-based FeSe2@C hollow structures exhibit high conductivity and special structural property which provide good charge transport kinetics by facilitating the charge transfer into the inner of FeSe2 nanorods. When used as anode materials for sodium ion batteries, the hierarchically hollow nanocubes showed excellent rate performance and ultra-stable long-term cycling stability at a high current density of 10 A g−1, suggesting a good sodium-ion storage material. This simple solid-phase process demonstrated in this work can be further used for the preparation of other metal selenide with unique and fascinating structure for the potential applications in the energy storage field.