氧化石墨烯掺杂量与pH值对石墨烯气凝胶储能性能的影响

采用溶胶凝胶法制备石墨烯气凝胶（GA），并研究了前驱液中的pH值与氧化石墨烯（GO）的质量分数对GA材料储能性能的影响。使用X射线粉末衍射（XRD）、X射线光电子能谱（XPS）、氮气吸脱附分析、扫描电子显微镜（SEM）对样品微观结构与形貌进行表征。用循环伏安（CV）、恒流充放电（CP）、电化学交流阻抗（EIS）测试了样品的电化学性能。结果表明，前驱液中的pH值及GO质量分数的不同会影响GA中团簇颗粒的大小和数量，进一步影响GA三维结构。在pH值为6.3、GO 的质量分数为1%时，制得的GA比表面积最大为530 m2?g?1，在1 A?g?1的电流密度下比电容高达364 F?g?1。此外，将该材料制成对称超级电容器具有高的库伦效率，在1 A?g?1下进行CP测试，得到电容器的比电容为98 F?g?1，循环800次后其循环稳定性能为初始比电容值的95.9%。 

Effects of graphene oxide doping content and pH on energy storage performance of graphene aerogel

The preparation of graphene aerogel (GA) by the sol-gel method has wide application prospects. In this study, the sol-gel method was used to prepare GA composites using resorcinol (R), formaldehyde (F), and graphene oxide (GO) as precursor materials and sodium carbonate (C) as the catalyst. The effects of the pH value and GO in the precursor solution on the energy storage performance of GA materials were studied. The microstructure and morphology of the samples were characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nitrogen desorption analysis, and scanning electron microscopy (SEM). Cyclic voltammetry (CV), constant current charge–discharge (CP) and electrochemical impedance spectroscopy (EIS) were used to measure the electrochemical properties of the samples in 1 mol?L?1 Na₂SO₄ electrolyte. The results show that different pH values and GO affect the size and number of cluster particles in GA and the three-dimensional structure of GA. When the pH value was 6.3 and the mass fraction of GO was 1% in the precursor solution, the obtained GA sample exhibited superior surface properties and electrochemical performance. At a current density of 1 A?g?1, the specific surface area of the GA was 530 m2?g?1, and the specific capacitance was 364 F?g?1. If the current density was increased to 10 A?g?1, the specific capacitance still reached 229 F?g?1, indicating that the GA sample had better multiplier performance. After 800 cycles at a current density of 1 A?g?1, the specific capacitance retention rate was 76%. In addition, the GA sample was utilized as a symmetrical supercapacitor with high coulomb efficiency. The specific capacitance of the capacitor remained at 98 F?g?1 in a constant current charge–discharge test at a current density of 1 A?g?1. After 800 cycles, a specific capacitance retention rate of 95.9% was maintained by the symmetrical supercapacitor. This study provides a method for improving the electrochemical properties of GA to realize supercapacitors with better performance.