Performance degradation study of NiCo(2)O(4)-based asymmetric supercapacitors

The performance of NiCo(2)O(4)//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 NiCo(2)O(4) electrode declined rapidly. Therefore, porous spherical NiCo(2)O(4) nanoparticles were synthesized via a simple hydrothermal method. A NiCo(2)O(4)//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 NiCo(2)O(4) electrode before and after the cycle, it was found that the performance of NiCo(2)O(4) electrode declines rapidly after the cycle due to the formation of new substances and the destruction of the crystal structure of NiCo(2)O(4) 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.