Metal-organic framework-derived CoSe2@N-doped carbon nanocubes for high-performance lithium-ion capacitors

Cobalt selenide (CoSe2) has garnered considerable attention as a prospective anode candidate for advanced lithium-ion storage, prompting comprehensive investigations. However, CoSe2-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 CoSe2 nanoparticles embedded in N-dope carbon skeleton (CoSe2@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 CoSe2. Owing to their unique nanostructure, the as-prepared CoSe2@NC exhibits a high capacity of 745.9 mAh<middle dot>g(-1) at 0.1 A<middle dot>g(-1), while maintaining excellent rate capability and an impressive lifespan. Furthermore, the assembled lithium-ion capacitor (LIC) based on CoSe2@NC demonstrates an energy density of 130 Wh<middle dot>kg(-1), a power density of 24.6 kW<middle dot>kg(-1), and remarkable capacity retention of 90.8% after 8000 cycles. These results highlight the great potential of CoSe2@NC for practical applications.