摘要
玻态炭的电导率高,机械性能好,但因制备费时长而价格昂贵,透气率极低而无法整体活化,难以用作电化学电容器的电极材料。为此提出了一种具有纳米结构多孔玻态炭的快捷制备方法:在热塑性酚醛树脂中加入适量的固化剂,经加热固化、粉碎研磨、模压成型、快速升温炭化、活化。这种酚醛树脂基纳米孔玻态炭整体呈多孔结构,由于比表面较大而可得大比容量,由于块体电导率较高和孔结构合适而可得大比功率。着重研究了制备方法中影响其电化学电容性能的重要影响因素-固化温度。研究结果表明,炭化物的孔隙率随固化温度升高而增大,利于活化剂分子向内扩散,增强活化反应的造孔作用。所制纳米孔玻态炭的结构介于玻态炭和活性炭之间,固化温度越高,孔结构越发达,其结构越趋近于活性炭。225℃以上固化,产物的孔结构和电化学性能较好,因此225℃作为固化温度较适宜。
Glassy carbon (GC) has high conductivity and good mechanical properties, but is costly due to the long preparation cycle and cannot be activated monolithically due to its extremely low penetrability. Therefore, it is impossible for GC to be used as electrode materials for electrochemical capacitors. A novel porous GC with a nanostructure with a shortened production route has been prepared. A hardening agent was added to a phenolic novalac resin, which was cured at temperatures below 250?℃. The cured resin was then crushed, ground, compacted to a disc, heated quickly to carbonization temperature and activated in flowing CO2, leading to the formation of monolithic nanoporous GC with a high capacity due to its large surface area, and high power density due to its good conductivity and proper pore structure. The key factor, the hardening temperature, which affects performance of electrochemical capacitors, is discussed in this paper. It is shown that the porosity of the carbonized resin increases with the hardening temperature, allowing the activation agent to diffuse inward and enhancing pore formation in the activation reaction. The structure of this nanoporous GC is between those of GC and activated carbon. Furthermore, the higher the hardening temperature, the more developed the pore structure. The products have a favorable pore structure and electrochemical performance when cured at temperatures above 225?℃.
出处
《新型炭材料》
SCIE
EI
CAS
CSCD
2003年第3期219-224,共6页
New Carbon Materials
基金
国家863项目
