Ni-derived electronic/ionic engineering on NiSe/Ni@C for ultrafast and stable sodium storage.

Atomic-level structure engineering has proven indispensable for fast ion transport kinetics. Herein, a unique framework of NiSe/Ni heterostructure with abundant heterointerface encapsulated hollow carbon spheres, namely NiSe/Ni@C, is synthesized as an anode for SIBs. The NiSe/Ni@C electrode delivers enhanced Na + storage performance in terms of high specific capacity (490 mA h g -1 ) and excellent rate capability (546 mA h g -1 ) at a current of 5.0 A g -1 over 2000 cycles. This study can provide in-depth insights into the interface effect in hybrid structures and shed light on designing energy storage materials.