Synergistic enhancement effect of activated carbon incorporation on the supercapacitor performance of CoFe-LDH

Layered double hydroxides (LDHs) show considerable potential as pseudocapacitive materials for supercapacitors; however, their electrical conductivity and cycling stability remain critical challenges for enhancing overall performance. In this study, pure CoFe-LDH and its composite series with activated carbon (AC) were successfully fabricated on nickel foam substrates via a hydrothermal method. The effects of AC addition on the microstructure and electrochemical behavior of the materials were systematically investigated using characterization techniques including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The results demonstrate that the composite material CoFe- LDH/AC15, prepared with an AC dosage of 15 mg, exhibits the most outstanding energy storage performance: a specific capacitance of 3993 F g -1 at a current density of 1 A g -1 , representing a 47.2% improvement compared to pure CoFe-LDH (2713 F g -1 ); furthermore, the capacity retention remains at 77.9% even at a high current density of 10 A g -1 , indicating excellent rate capability. The cycling durability test shows that the electrode material retains 42% of its initial capacitance after 5,000 charge-discharge cycles at a current density of 5 A g -1 . This study confirms that the synergistic enhancement between AC and CoFe-LDH significantly improves the electrical conductivity and structural stability of the composite materials, effectively boosting the overall electrochemical performance, which holds important significance for the development of high-performance supercapacitor electrode materials.