超级电容器用富氮炭电极材料制备及性能表征

Preparation and characterization of nitrogen-containing activated carbon electrode materials for supercapacitor

活性炭具有制备简单、成本低、比表面积大、导电性好以及化学稳定性高等特点,作为超级电容器电极材料已得到广泛应用。由于活性炭的储能性能有限,在活性炭中引入氮原子,利用氮原子的准电容效应来提高活性炭材料的比电容是制备高比容量炭电极材料的一个重要途径。以价格低廉、来源广泛的煤为原料,以三聚氰胺为改性剂制备富氮活性炭电极材料。采用N2吸附法、元素分析及电化学测试对活性炭的孔隙结构、元素组成和电化学性能进行分析,研究了三聚氰胺改性对活性炭电极材料的电化学性能的影响。结果表明:当活性炭与改性剂的浸渍比为3∶2时,活性炭电极材料的BET比表面积从改性前的1 300 m2/g下降到1 082 m2/g,其氮元素含量相应从0.56%增加到4.13%,氮原子在活性炭表面形成含氮官能团(如N-6、N-5、N-X),50 mA/g电流密度下的比电容由165 F/g上升到188 F/g。

Activated carbon has been used widely as the supercapacitor electrode material for its easy availability, low cost, high specific surface area, excellent electrical conductivity and chemical stability. Due to limited storage performance of activated carbon, the introduction of nitrogen atoms, nitrogen atoms in the quasi-capacitance effects to improve the specific capacitance of activated carbon materials is an important way for preparation of high specific capacity of carbon electrode material. N-enriched activated carbons were prepared from cheap source of a wide range of coal using melamine as an activating agent for electrochemical capacitors. Porous structure, elemental composition and electrochemical characteristics of the carbons were investigated by nitrogen sorption, elemental analysis and electrochemical methods, respectively. The effect of modifying with melamine on the electrochemical performance of the as prepared carbons was studied. The results show that when the activated carbons impregnate with melamine according to the ratio of 3 ： 2, the BET specific surface area of the sample decreases from 1 300 m2/g to 1 082 m2/g, the mass fraction N increases from 0.56% to 4.13%, the nitrogen atom exists in the surface of carbon （N-6, N-5, N-X）and under 50 mA/g the capacitance increases from 165 F/g to 188 F/g.