Double-layer carbon encapsulated with iron-doped cobalt hydroxide on Cu2O for high-performance supercapacitor anode

Due to the increasing prominence of energy and environmental issues, the output performance and safety of energy storage devices are becoming more and more important. To address this dilemma, and an interesting approach has been proposed to rationally design porous carbon derived from cobalt-based metal-organic frameworks (ZIF-67) on copper foams and to further optimize the ratio of iron ions in cobalt hydroxide based on Cu₂O/nanoporous carbon (Cu₂O/NPC). Finally, an anode material was obtained by electrodepositing it on polypyrrole (PPy) nanowires. The resulting Cu₂O/NPC@CoFe_0.15(OH)_x/PPy-20 (CNCF0.15P2) material was endowed with excellent electrochemical properties up to 11.8 F·cm^-2 with almost no attenuation for 2500 cycles. Favorable charge transfer morphology, lower diffusion resistance and more resistant structural stability are responsible for the superior activity and cycling performance. Furthermore, an asymmetric device utilizing the CNCF0.15P2 electrode alongside a cobalt-nickel bimetallic hydroxide electrode achieves an impressive energy density of up to 0.44 mWh·cm^-2 at 2.4 mW·cm^-2, demonstrating remarkable cycling performance. This study demonstrates that the CNCF0.15P2 negative electrode is a promising option for energy storage devices and offers valuable insights for the development of copper-based supercapacitors.