聚酰亚胺基高比表面活性炭及其电化学性能研究

以聚酰亚胺(PI)薄膜边角料为前驱体, 采用CO₂物理活化法制备高比表面活性炭。研究了活化工艺对PI活性炭孔结构性能的影响及其活化机理, 探讨了活性炭孔结构对其电化学性能的影响。结果表明, PI薄膜可以在相对较低的温度下经CO₂活化制备出具有无定型微晶质炭结构、孔隙结构发达的活性炭, 比表面积最高可达2809 m²/g, 总孔容积达1.423 cm³/g; 通过控制CO₂活化工艺, 可实现对PI活性炭的孔道尺度与分布的调控。作为超级电容器电极材料, PI活性炭在100 mA/g条件下, 比电容高达237 F/g, 电容保持率为86%。孔径集中于0.7~2 nm, 并存在适量介孔的活性炭具有极佳的电化学性能。

Preparation and Electrochemical Performance of Polyimide-based Activated Carbons with High Surface Area

Polyimide-based activated carbon (PIAC) was prepared by CO₂ activation using polyimide (PI) film offcut as precursor. The influences of activation conditions on the pore structure of PI-based activated carbons and the activation mechanism were investigated. Effects of pore structure on electrochemical properties of PIAC were also investigated. Results show that the PI film offcuts can be used to prepare the PI-based activated carbon with high surface area, abundant porosity and amorphous carbon structure at relatively low temperature via CO₂ activation, in which the highest specific surface area was 2809 m²/g with pore volume of 1.423 cm³/g. Pore size and distribution of activated carbon can effectively be concentrated at 0.7-2 nm with proper mesopores by controlling CO₂ activation time. As an electrode material, PIAC shows an excellent electrochemical performance with specific capacitance of up to 237 F/g at current density of 100 mA/g and capacitance retention of 86%.