Construction of flower-like spherical CoFe2O4@Co3O4 based on zeolitic imidazolate framework as high-performance electrode materials for supercapacitors

Ferrite, a class of transition metal oxides, has emerged as a promising material for electrochemical energy storage due to its cost-effectiveness and high theoretical capacity. However, the tendency of ferrite to agglomerate hinders its practical application. Here, we report a facile method to fabricate CoFe2O4@Co3O4 flower-like sphere and form a unique core-shell structure. In this composite, flake Co3O4 pile up to form shell which cladding the CoFe2O4 core. Crumpled shell provide ultra-high specific surface area (128.54 m2/g) to expose more electrochemical active sites, benefiting effective electrons transfer. As a result, the optimized flower-like spherical structure electrode exhibited an exceptionally high capacity of 2834 F g−1 at a current density of 1 A g−1. Additionally, the electrode demonstrated outstanding rate capability, retaining 78 % of its capacity at a current density of 10 A g−1. •The flower-like spherical Co3O4@CoFe2O4 were successfully synthesized.•CoFe-ZIF with crumpled surface were successfully synthesized using benzimidazole as organic ligand.•Ultrahigh specific capacity of 2834 F g−1 is achieved.•The dynamics of electrochemical reactions was investigated.