由微孔棒状羟基磷灰石为模板合成的新型层次孔炭材料的电化学电容性能

电化学电容器已经成为极具潜力的可满足高功率需求的储能系统器件. 多孔炭具有大比表面积、高导电性、化学惰性、廉价及可调孔结构等优势, 因此成为电化学电容器最为常用的电极材料. 本文报道由微孔棒状羟基磷灰石为模板及蔗糖为碳源合成的新型具有层次孔道结构的孔炭材料的电化学电容器的性能. 采用X射线衍射分析仪、扫描电子显微镜、透射电子显微镜、X射线光电子能谱及BET表面分析仪表征了合成的多孔炭的形貌及表面特性. 采用循环伏安法、交流阻抗图谱分析及恒流充放电评价多孔炭材料在1 mol·L^-1硫酸中的电化学电容性能. 多孔炭具有高的比表面积(719.7 m²·g^-1)和大的孔容(1.32 cm³·g^-1), 其无序的孔道由任意分布的微孔、坍塌的中孔及类模板形状的相互交织的棒状中孔组成. 随着炭化温度的增加, 微孔及棒状中孔的密度随之降低, 在炭化温度高达900℃时, 孔径分布图上出现了三个峰. 正是由于这些特殊的结构特征, 由900℃炭化得到的多孔炭制成的电极展示出很好的电化学电容性能.

Synthesis and Electrochemical Capacitive Performances of Novel Hierarchically Micro-Meso-Structured Porous Carbons Fabricated Using Microporous Rod-Like Hydroxyapatites as a Template

Electrochemical capacitors (ECs) are attractive energy storage systems for applications with high power requirements. Porous carbons are the materials that are most frequently used for the electrodes in ECs, because of their large surface area, high conductivity, chemical inertness, low cost, and tunable pore structure. Here, novel hierarchically micro-meso-structured porous carbons were synthesized, using microporous rod-like hydroxyapatite nanoparticles as a template and sucrose as a carbon source. The morphology and surface properties of the as-prepared porous carbons were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller surface analysis. The electrochemical capacitive performances were evaluated in an aqueous solution of 1 mol·L^-1 H₂SO₄ using cyclic voltammetry, electrochemical impedance spectroscopy, and constant current charge/discharge tests. The resultant carbons showed a high surface area of more than 719.7 m²·g^-1, large pore volumes of more than 1.32 cm³·g^-1, and a disordered pore structure composed of randomly distributed micropores, collapsed mesopores, and interweaving rod-like mesopores that took the shape of the template. As the carbonization temperature was increased, the density of micropores and rod-like mesopores decreased, and a tri-modal pore size distribution appeared for the carbon sample carbonized at 900 ° C. Because of these unique characteristics, the electrode material originated from the porous carbon carbonized at 900℃ exhibited good electrochemical capacitive performances.