Performance degradation study of NiCo₂O₄-based asymmetric supercapacitors

The performance of NiCo₂O₄//GO asymmetric supercapacitors was found to decline after many tests. It was found that the performance of the GO electrode was almost unchanged, while the performance of the NiCo₂O₄ electrode declined rapidly. Therefore, porous spherical NiCo₂O₄ nanoparticles were synthesized via a simple hydrothermal method. A NiCo₂O₄//GO asymmetric supercapacitor was made, which can be charged and discharged 3000 times in the current density of 10 A g^-1. The surface morphology, crystal structure and elemental composition were characterized by X-ray diffraction analysis, scanning electron microscopy and X-ray photoelectron spectroscopy. By comparing the surface morphology, crystal structure and elemental composition of the NiCo₂O₄ electrode before and after the cycle, it was found that the performance of NiCo₂O₄ electrode declines rapidly after the cycle due to the formation of new substances and the destruction of the crystal structure of NiCo₂O₄ electrode. Therefore, maintaining the stability of the crystal structure of the electrode material is an important means to ensure the stability of the performance of the supercapacitor. It provides a meaningful strategy for studying the degradation of supercapacitor electrode materials.