ZIF-67衍生氮掺杂多孔碳的可控制备及其电化学性能

Controlled preparation of ZIF-67-derived nitrogen-doped porous carbon and its electrochemical properties

多孔碳材料优良的导电性、液体渗透性和高的热稳定性使其在能源存储与转化领域受到广泛关注。通过在多孔碳材料内部引入含氮元素可进一步提高其电化学性能。本文以金属有机框架ZIF-67为前驱体,通过一步高温热分解法成功制备富含氮元素的钴包覆多孔碳材料(Co@NC)。研究了碳化温度(600℃、700℃、800℃)对Co@NC复合多孔碳材料的形貌、结构和电化学性能的影响。最优的多孔碳材料Co@NC-700在1 A·g^(-1)电流密度下比电容可以达到114.2 F·g^(-1),当电流密度达到10 A·g^(-1)时电容保留64.8%,表明较好的倍率性能。将Co@NC-700产物组装对称电容器,在功率密度为250.1 W·kg^(-1)时最大能量密度达到4.1 Wh·kg^(-1)。进行5000圈循环充放电,比电容仍保留82.3%。上述结果表明该方法制备的Co@NC多孔碳材料作为超级电容器负极具有很大的应用潜力。

Porous carbon materials have attracted extensive attention in the field of energy storage and conversion due to their excellent electrical conductivity,liquid permeability and high thermal stability.The electrochemical performance of porous carbon materials can be further improved by introducing nitrogen elements into the porous carbon materials.In this paper,porous carbon materials(Co@NC)containing nitrogen and the embedded cobalt were successfully prepared by one-step high-temperature thermal decomposition using metal-organic framework ZIF-67 as the precursor.The effects of carbonization temperature(600℃,700℃,800℃)on the morphology,structure and electrochemical properties of Co@NC porous carbon composites were studied.The specific capacitance of the optimal porous carbon material Co@NC-700 can reach 114.2 F·g^(-1) at the current density of 1 A·g^(-1),and the capacitance retention is 64.8%when the current density reaches 10 A·g^(-1),indicating a better rate performance.The Co@NC-700 product is assembled into a symmetric capacitor to achieve a maximum energy density of 4.1 Wh·kg^(-1) at a power density of 250.1 W·kg^(-1).After 5000 cycles of charging and discharging,82.3%of the specific capacitance is still retained.These results indicate that the Co@NC porous carbon material prepared by this method has great application potential as the negative electrode of supercapacitor.