Tailored core/shell design: Co_0.85Se nanowires embedded in NiCo-LDH for superior battery-type supercapacitor applications

This paper reports the successful synthesis of a novel core/shell structure featuring cobalt selenide nanowires coated with nickel–cobalt layered double hydroxide (Co_0.85Se@NiCo-LDH). Co_0.85Se nanowires were encapsulated within NiCo-LDH nanosheets on a nickel foam (NF) substrate using a facile three-step synthesis method. Initially, core cobalt carbonate hydroxide hydrate nanowires (CCHH) were grown on an NF substrate using a hydrothermal approach. The Co_0.85Se nanowires were then obtained using a selenization process. Finally, a NiCo-LDH nanosheet shell was deposited via an electrodeposition method. The resulting Co_0.85Se@NiCo-LDH material exhibited a remarkable specific capacity of 1314C g⁻¹ at 1.0 A g⁻¹ owing to its unique core/shell architecture and composition, demonstrating exceptional rate capability with a performance retention of 61.5 % even at a high current density of 20 A g⁻¹. Moreover, it displayed remarkable cycling stability, retaining 89.2 % of its initial capacity after 10,000 cycles. A hybrid supercapacitor device was constructed using Co_0.85Se@NiCo-LDH as the positive electrode and activated carbon as the negative electrode. This configuration yielded an impressive energy density of 72.2 Wh kg⁻¹ and a high-power density of 849.9 W kg⁻¹, while maintaining excellent cycling stability with 88.2 % retention after 10,000 cycles. These findings highlight the potential of core/shell architectures for developing high-performance supercapacitors with improved kinetics and stability.