Multifunctional pompon flower-like nickel ferrites as novel pseudocapacitive electrode materials and advanced absorbing materials

Abstract The pompon flower-like nickel ferrites (PF–NiFe2O4) were prepared by a vapor diffusion-deposition method followed by annealing process. The pseudocapacitive performance and microwave absorbing property of as-obtained multifunctional PF-NiFe2O4 were investigated. The PF-NiFe2O4 yielded the specific capacitance of 168.5 F g-1 at the current density of 1 A g-1 and 98.8 F g-1 at 10 A g-1, while the corresponding values were 140.9 and 65.3 F g-1 for their bulk counterpart, indicating good capacitive performance of PF-NiFe2O4. Furthermore, the bulk NiFe2O4 electrode collapsed after about 5100 cycles, whereas the PF-NiFe2O4 remained 71.4% of capacitance after 10000 cycles at 1 A g-1, unveiling good cyclic performance. In addition, the PF-NiFe2O4 exhibited the minimum reflection loss of -18.3 dB, while the bulk NiFe2O4 only yielded the minimum reflection loss of -9.2 dB. The unique pompon flower-like structure was crucial for the enhanced capacitive performances and absorbing properties. These multifunctional features made the PF-NiFe2O4 a promising candidate in pseudocapacitor electrodes and microwave absorbing application.