Selenium-doped Se-CoSe2@ZnSe heterojunction structure derived from ZIF-8 metal organic skeleton is used in high-performance asymmetric supercapacitors

Reasonable construction of multi-pore heterogeneous structures and enhancement of synergistic interaction between metal ions are important means to improve the performance of supercapacitors . This work selected metal organic frameworks (MOF) as the sacrificial template, and Se-doped needle-like nanosphere heterostructures Se-CoSe 2 @ZnSe were successfully prepared by in situ growth and selenization treatment. The specific capacity of the Se-CoSe 2 @ZnSe-5 (CZS-5) electrode is up to 2469.12 F g −1 at 1 A g −1 , and the capacity retention rate of 3000 cycles at a current density of 10 A g −1 is 85.39 %. The CZS-5//AC hybrid supercapacitor has a high power density of 1280.00 W kg −1 at an energy density of 68.88 Wh kg −1 . The excellent electrochemical properties are attributed to the construction of Se-CoSe 2 @ZnSe heterostructure of needle-shaped nanospheres enhances the synergy between Zn and Co ions; the doping of selenium effectively improves the conductivity of the electrode material; selenium vacancies produced during selenization increase the activity of the active site. In addition, the density functional theory (DFT) calculation shows that Se-CoSe 2 @ZnSe-5 has higher density of states (DOS) near the Fermi energy level, which provides additional theoretical support for the improvement of electrochemical performance.