Facile synthesis and electrochemical properties of alicyclic polyimides based carbon microflowers for electrode materials of supercapacitors

Polyimide(PI) as the precursor of carbon materials for electrodes of supercapacitor has attracted extensive attention. Herein, a kind of porous carbon materials derived from alicyclic polyimides were fabricated by the solvothermal approach to form PI microflowers, followed by further pyrolysis. Due to the thermal instability of alicyclic structures derived from cyclobutane-1,2,3,4-tetracarboxylic dianhydride(CBDA), the carbon microflowers showed rich micro/mesoporous structures and large specific surface areas. The structures and electrochemical performance of the carbon microflowers were studied by adjusting precursor solution concentrations and final carbonizing temperatures. When the precursor concentration was 45 mg mL−1 and carbonization temperature was 800 °C, PIDMAc-45-800 performed the best electrochemical behaviors with the specific capacitance of 239.6 F g−1 at the current density of 0.5 A g−1. As the current density increased to 10 A g−1, the retention rate of specific capacitance reached 80.9%. After assembled a symmetric electrode, it exhibited high cycling stability with a negligible 0.1% capacitance reduction after 10,000 cycles at a current density of 1 A g−1. Moreover, after being placed for one year, the electrochemical performance of the cells decreased slightly, indicating good stability and reliability. Thus, the work offers a facile method to construct the N and O-doped and porous carbon microflower materials by virtue of the alicyclic PI as precursors, which will play an important role in the field of energy storage and conversion.