A General Metal-Organic Framework (MOF)-Derived Selenidation Strategy for In Situ Carbon-Encapsulated Metal Selenides as High-Rate Anodes for Na-Ion Batteries

On account of increasing demand for energy storage devices, sodium-ion batteries (SIBs) with abundant reserve, low cost, and similar electrochemical properties have the potential to partly replace the commercial lithium-ion batteries. In this study, a facile metal-organic framework (MOF)-derived selenidation strategy to synthesize in situ carbon-encapsulated selenides as superior anode for SIBs is rationally designed. These selenides with particular micro-and nanostructured features deliver ultrastable cycling performance at high charge-discharge rate and demonstrate ultraexcellent rate capability. For example, the uniform peapod-like Fe7Se8@C nanorods represent a high specific capacity of 218 mAh g(-1) after 500 cycles at 3 A g(-1) and the porous NiSe@C spheres display a high specific capacity of 160 mAh g(-1) after 2000 cycles at 3 A g(-1). The current simple MOF-derived method could be a promising strategy for boosting the development of new functional inorganic materials for energy storage, catalysis, and sensors.