Z-scheme heterostructures confining rGO/protonated C3N5 junction supported CoCu LDH positive electrode and Fe3O4 negative electrode for supercapacitors

Abstract

CoCu LDH stabilized reduced graphene oxide-linked N-rich protonated C₃N₅ (Co_xCu_y@rGO/P–CN) as a power source Z-scheme nanocomposite was rationally tailored engineered an electrodeposition approach. The electrochemical performance was regulated by adjusting the electrodeposition potential and manipulating the Co/Cu molar ratio. Hence, affording compelling evidence for fine-tuning the performance of pseudo-active compounds. Benefiting from abundant heterointerfaces and synergistic effects between LDH nanoarrays and rGO/P–CN heterojunction, the hierarchical −1.2V Co₃Cu₁@rGO/P–CN Z-scheme positive electrode achieves a higher capacitance of 1184 F g⁻¹ at 1 A g⁻¹ and good rate capability performance. Theoretical simulation outcomes illustrate that the Co₃Cu₁@rGO/P–CN nanocomposite has higher electronic conductivity and superior electronic transition capability, originating from robust interactions between valence and conduction bands, interfacial charge transfer, and built-in electric field at the LDH/rGO/P–CN interface. We also explore the Fe₃O₄@rGO/P–CN Z-scheme as a negative electrode material via a simple annealing process with a capacitance of 402 F g⁻¹ at 1 A g⁻¹ and an enhanced cyclic performance. Consequently, the as-assembled −1.2V Co₃Cu₁@rGO/P–CN//Fe₃O₄@rGO/P–CN asymmetric supercapacitor (ASC) cell acquires a remarkable energy density of 63.4 Wh kg⁻¹ at 750 W kg⁻¹ and displays an exceptional cycling activity with 88 % retention after 11,000 cycles.