Synthesis of Copper‐Substituted CoS2@CuxS Double‐Shelled Nanoboxes by Sequential Ion Exchange for Efficient Sodium Storage

The construction of hybrid architectures for electrode materials has been demonstrated as an efficient strategy to boost sodium‐storage properties because of the synergetic effect of each component. However, the fabrication of hybrid nanostructures with a rational structure and desired composition for effective sodium storage is still challenging. In this study, an integrated nanostructure composed of copper‐substituted CoS2@CuxS double‐shelled nanoboxes (denoted as Cu‐CoS2@CuxS DSNBs) was synthesized through a rational metal–organic framework (MOF)‐based templating strategy. The unique shell configuration and complex composition endow the Cu‐CoS2@CuxS DSNBs with enhanced electrochemical performance in terms of superior rate capability and stable cyclability.