Temperature‐Regulated Morphological Evolution of NiCo‐Carbonate‐Layered Double Hydroxides for High‐Performance Supercapacitor Electrodes

ABSTRACT Supercapacitors, renowned for their advantages of low‐cost, high‐power density, excellent cycling stability, environmental benignity, and superior safety have gained widespread application in diverse fields. However, their further development is limited by drawbacks such as low energy density. NiCo‐carbonate layered double hydroxide (NiCo‐Carbonate LDH) is a promising electrode material, but its two‐dimensional (2D) nanostructures tend to agglomerate, reducing capacitance utilization. In this study, using nickel foam (NF) as the growth substrate, we systematically elucidate, for the first time, the temperature‐induced morphological evolution mechanism of NiCo‐Carbonate LDH from sheet‐like to needle‐like nanostructures by regulating hydrothermal temperature, and fabricate NiCo‐Carbonate LDH/NF composites with a unique needle‐like array architecture. By further optimizing reduced graphene oxide (rGO) loading, we construct NiCo‐Carbonate LDH/rGO/NF composite electrodes. The optimized NiCo‐Carbonate LDH/rGO/NF‐2 electrode delivers a remarkable specific capacitance of 1519 F·g −1 at 1 A·g −1 , which is attributed to the synergistic effect of the needle‐like structure and rGO‐effectively suppressing rGO restacking and promoting ion diffusion and electron transport. The charge storage mechanism is dominated by diffusion‐controlled processes, with the capacitive contribution increasing to 45.2% at high scan rates. This work provides a facile and effective strategy for designing high‐performance supercapacitor electrodes.