Dense NiCo2 O4 Nanoneedles Grown on Carbon Foam Showing Excellent Electrochemical and Microwave Absorption Properties.

Electromagnetic pollution could harm sensitive electronic equipment due to the rising use of electronic devices and communication infrastructure. The supercapacitor's electrochemical performance should be enhanced, and electromagnetic damage should be prevented. This study proposes NiCo2 O4 /CF composites for supercapacitors and microwave absorption. They are made by combining hydrothermal and annealing processes. Dense NiCo2 O4 nanoneedles were uniformly grown on the outer layer of carbon foam (CF) as a growth skeleton, preventing the agglomeration of NiCo2 O4 . The composite had a specific capacitance of 537.5 F/g at 1 A/g. When the current density was set to 1 A/g, the supercapacitor that used NiCo2 O4 /CF as the cathode had a specific capacitance of 70.7 F/g, and when the current density was increased to 10 A/g, the original specific capacitance of 87.2 % could still be maintained after 5000 charge-discharge cycles. At a power density of 3695.5 W/kg, an energy density of 22.1 Wh/kg could be maintained. Furthermore, we performed a microwave absorption test and determined its reflection loss curve for various sample thicknesses. Recombination enhanced the composite material's microwave absorption capability by greatly reducing the dielectric loss and the magnetic loss.