Functional integration of hierarchical core–shell architectures via vertically arrayed ultrathin CuSe nanosheets decorated on hollow CuS microcages targeting highly effective sodium-ion storage

A hierarchical core–shell architecture of vertically arrayed ultrathin CuSe nanosheets decorating on hollow CuS microcages affords exceptional sodium storage performance with an admirable 303.1 mA h g −1 at 20.0 A g −1 after 1500 cycles.