Polyurethane and polyaniline foam-derived nickel oxide-incorporated porous carbon composite for high-performance supercapacitors

A new type of polyurethane and polyaniline foam-derived nickel oxide-incorporated porous carbon composite (PPFPC-NiO) was synthesized through a combination of in situ polymerization, chemical blowing and carbonization methods and was studied for the first time. By taking advantage of a polyaniline-introduced polyurethane foam as a porous carbon skeleton precursor, interconnected nickel oxide-incorporated nanowires provided hierarchical porous conductive network structures after carbonization treatment, forming stable three-dimensional coralline-like open nano-architectures, which not only enhance the electrical conductivity and accelerate the electron transport rate during the charge–discharge process but also provide myriads of open hierarchical porous channels for rapid ion diffusion, increasing the number of available reactive sites in the PPFPC-NiO. As an electrode in supercapacitors, the PPFPC-NiO exhibits a high specific capacitance of 1012.8 F g⁻¹ at 1 A g⁻¹, with a capacitance retention of 96.43% after 5000 cycles in a three-electrode test and with 6 M KOH as the electrolyte. Because of these properties, an asymmetric supercapacitor is assembled using the PPFPC-NiO as the positive electrode and a mixture of activated carbon and graphite as the negative electrode. In a potential window of 1.5 V, the capacitor exhibits a high energy density of 32.2 Wh kg⁻¹ at a power density of 281.3 W kg⁻¹, which remains at 22.5 Wh kg⁻¹, even at a high-power density of 1472.7 W kg⁻¹. More importantly, the capacitor also shows excellent cycling stability, with 92.71% capacitance retention after 5000 cycles.