Preparation of a NiAl-Oxide@Polypyrrole Composite for High-Performance Supercapacitors

A core-shell NiAlO@polypyrrole composite (NiAlO@PPy) with a 3D "sand rose"-like morphology was prepared via a facile in situ oxidative polymerization of pyrrole monomer, where the role of PPy coating thickness was investigated for high-performance supercapacitors. Microstructure analyses indicated that the PPy was successfully coated onto the NiAlO surface to form a core-shell structure. The NiAlO@PPy exhibited a better electrochemical performance than pure NiAlO, and the moderate thickness of the PPy shell layer was beneficial for expediting the electron transfer in the redox reaction. It was found that the NiAlO@PPy₅ prepared at 5.0 mL L^-1 addition amount of pyrrole monomer demonstrated the best electrochemical performance with a high specific capacitance of 883.2 F g^-1 at a current density of 1 A g^-1 and excellent capacitance retention of 91.82 % of its initial capacitance after 1000 cycles at 3 A g^-1 . The outstanding electrochemical performance of NiAlO@PPy₅ were due to the synergistic effect of NiAlO and PPy, where the uniform network-like PPy shell with the optimal thickness made electrolyte ions more easily accessible for faradic reactions. This work provided a simple approach for designing organic-inorganic core-shell materials as high-performance electrode materials for electrochemical supercapacitors.