Metal–organic framework‐derived CoSe 2 @N‐doped carbon nanocubes for high‐performance lithium‐ion capacitors

Abstract Cobalt selenide (CoSe 2 ) has garnered considerable attention as a prospective anode candidate for advanced lithium‐ion storage, prompting comprehensive investigations. However, CoSe 2 ‐based anodes usually suffer from significant volume variation upon lithiation, leading to unsatisfactory cycling stability. Herein, a versatile synthesis route is proposed for the in‐situ fabrication of CoSe 2 nanoparticles embedded in N‐dope carbon skeleton (CoSe 2 @NC) through annealing treatment and selenization of a metal–organic framework‐derived (MOF) precursor. The N‐doped carbon derived from the MOF serves not only as an excellent conductive substrate but also as a confined reactor, effectively inhibiting the structural instability and alleviating the inevitable volume change of CoSe 2 . Owing to their unique nanostructure, the as‐prepared CoSe 2 @NC exhibits a high capacity of 745.9 mAh·g −1 at 0.1 A·g −1 , while maintaining excellent rate capability and an impressive lifespan. Furthermore, the assembled lithium‐ion capacitor (LIC) based on CoSe 2 @NC demonstrates an energy density of 130 Wh·kg −1 , a power density of 24.6 kW·kg −1 , and remarkable capacity retention of 90.8% after 8000 cycles. These results highlight the great potential of CoSe 2 @NC for practical applications.