Hydrothermal nanoarchitectonics of NiFe layered double hydroxides/FeOOH/graphene oxide composite electrode for enhancement of electrochemical performance

In response to the key issues such as poor conductivity, insufficient active sites, and complex preparation processes associated with nickel‑iron layered double hydroxide (NiFe-LDH) and iron oxyhydroxide (FeOOH) electrode materials, this study proposed an innovative solution. A one-step hydrothermal method was employed to directly synthesize the NiFe-LDH/FeOOH composite on a 3D nickel foam substrate, and further prepared the NiFe-LDH/FeOOH/graphene oxide (GO) composite. Through a series of physicochemical characterization techniques, the positive effects of GO doping on the microstructure and electrochemical performance of the composites were systematically investigated. The experimental results showed that under the optimized condition with a GO concentration of 0.208 mg mL⁻¹, the NiFe-LDH/FeOOH/GO composite electrode exhibited excellent electrochemical performance. At current densities of 1, 3, 5, 7, and 10 A g⁻¹, its specific capacitances reached 1813.3, 1580.7, 1416.7, 1288.3, and 1133.8 F g⁻¹ respectively, which were significantly superior to those of the NiFe-LDH/FeOOH composite under the same conditions (1726.7, 1495.3, 1341.1, 1218.8, and 1054.4 F g⁻¹ respectively). In terms of high-current-density performance, at a current density of 10 A g⁻¹, the capacitance retention rate of the NiFe-LDH/FeOOH/GO composite electrode was as high as 62.5 %, significantly better than the 60.1 % of the NiFe-LDH/FeOOH composite. In the cycle stability test, at a current density of 3 A g⁻¹, after 1000 charge-discharge cycles, the capacity retention rate of the NiFe-LDH/FeOOH/GO composite was 69.0 %, far higher than the 22.3 % of the NiFe-LDH/FeOOH material. Even after 5000 cycles, although its capacity retention rate dropped to 25.4 %, it was still higher than the 14.4 % of the NiFe-LDH/FeOOH material. The results of this study provided new ideas for the design of supercapacitor electrode materials with high capacity and high-rate performance and made an important contribution to the development of nanoscale energy materials.