Porous Silicon Composite ZnO Nanoparticles as Supercapacitor Electrodes

Porous electrode composite materials with a large surface area and suitable pore size, as well as a short diffusion distance of electrolyte ions in the pore channels, are greatly desired for supercapacitor electrodes. Porous silicon composite zinc oxide nanoparticles with a high cycling performance and stability have been prepared by vacuum filtration, combined with homogenizing and hydrothermal methods. The composite material has a 3.9 mF/g specific capacitance, which is an increase of 40 times when compared to pure porous silicon. The results show that the composite materials can effectively passivate the porous silicon surface, improving the porous silicon capacitor's characteristics and stability. This investigation is helpful in understanding the surface modification of porous silicon, and also indicates a potential method for designing porous electrode composite materials based on porous silicon and zinc oxide nanoparticles. Graphical Abstract The vacuum filtration was chosen to prepare porous silicon composite ZnO nanoparticles materials. It shows that ZnO adheres to the surface of the porous silicon and the inside of the pore walls more uniformly. The specific capacitance of the composite material is 3.9 mF/g, which is 40 times higher than that of pure porous silicon. The modified electrode not only has improved capacitance characteristics but also has good stability. Testing the impedance of the electrode shows that the modified electrode resistance has been improved to a certain extent, while the surface stability and the charge and discharge performance of the composite electrode have been greatly improved. Experiments showed that the use of ZnO can effectively improve the electrical properties of porous silicon, which provides ideas and experimental references for further expanding the application fields of porous silicon.