C-ZIF-8@AC复合电极材料的制备及超电容性能研究

在铅酸电池中添加一定量的碳可以同时发挥铅酸电池和超级电容器的优点，从而得到铅炭电池。因此，制备出在酸性溶液中稳定存在且具有理想比电容的碳材料尤为关键。通过低温液相和高温煅烧合成了一种新型的碳材料C-ZIF-8@活性炭(C-ZIF-8@AC)，将其作为铅炭电池电极材料。采用场发射扫描电子显微镜(FESEM)、高分辨透射电子显微镜(HRTEM)、X射线光电子能谱(XPS)和傅里叶红外光谱仪(FTIR)等对材料形貌和组成进行表征。结果显示，具有ZIF-8多面体结构的碳均匀生长于活性炭表面，且颗粒尺寸均一，与活性炭复合后的C-ZIF-8尺寸减小。电化学结果显示，C-ZIF-8框架结构中吡啶氮与吡咯氮中的氮元素提高了C-ZIF-8@AC的比电容性能，其值约为181 F/g，远大于AC电容值；在电流密度为5 A/g、循环6000周次后，C-ZIF-8@AC的比电容依然能够保持99%，高于活性炭的保持率。

Preparation and Supercapacitance of C-ZIF-8@AC Composites Electrode Material

A lead-carbon battery, which possesses simultaneously advantages of lead-acid battery and supercapacitor, can be obtained by adding a certain amount of carbon into the lead-acid battery. So, it is particularly critical to create a new type of carbon with ideal specific capacitance and stability in acid solutions. We tried to synthesize such a new carbon material namely C-ZIF-8@AC via a two step process i.e. low temperature liquid phase method and high temperature calcination. The materials were characterized by field emission scanning electron microscope (FESEM), high resolution transmission electron microscope (HRTEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectrometer (FTIR) etc. The results show that the prepared C-ZIF-8@AC composed of carbon particles with polyhedral structure (ZIF-8 framework) grown uniformly on the surface of active carbon (AC) particles; After ZIF-8 has further been coupled with AC particles, the size of the formed C-ZIF-8 particles is reduced. Electrochemical results indicate that the elemental N in pyridine nitrogen and pyrropyrrole nitrogen of the C-ZIF-8 framework can enhance the specific capacitance of C-ZIF-8@AC, which is about 181 F/g, much higher than that of the simple AC. The C-ZIF-8@AC shows excellent cycling stability with 99% capacitance retention rate after 6000 cycles at the current density of 5 A/g, which is higher than that of the simple AC.