Nitrogen-Doped Wrinkled Carbon Foils Derived from MOF Nanosheets for Superior Sodium Storage

Preparation of hierarchical carbon nanomaterials from metal-organicframeworks (MOFs) offers immense potential in the improvement of energy density, tunability, and stability of functional materials for energy storage and conversion. How interconnected nitrogen (N)-doped wrinkled carbon foils derived from MOF nanosheets can serve as high-performance sodium storage materials due to their multiscale porous structure is shown here. The novel N-doped carbon nanomaterials are synthesized through the pyrolysis of 2D Mn-based MOFs, which are produced through the assistance of monodentate ligands to enable the planar growth of MOFs. Subsequent acid etching creates hierarchical pores and channels to allow rapid ion transport. The resulting materials achieve high-rate capability (165 and 150 mA h g(-1) at current densities of 8 and 10 A g(-1), respectively) and high stability (capacity retention 72.8% after 1000 cycling at 1.0 A g(-1)), when they are used as anode in sodium-ion capacitors.