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·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 CoSe₂@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 CoSe₂@NC for practical applications.