| Because carbon materials possess the advantage of rich raw materials, low cost and special physico-chemical properties, they have been widely used in many fields such as catalyst, purifying sewage and storage of gas, especially in supercapacitors and lithium ion batteries. Recently, carbon materials have been paid more and more attention by scientists. In this paper, the nitrogen-containing activated carbons have been prepared from polyaniline (PANI) by activation with different activation reagent, such as H3PO4, KOH and mixed gas of nitrogen and oxygen. The nitrogen-containing activated carbons have been applied in supercapacitors and lithium ion batteries, the main contents of the paper are as follows:1. Nitrogen-containing activated carbons have been prepared from PANI by H3PO4 activation for supercapacitors. L9 (34) orthogonal experiments were employed in finding the optimum technological conditions of the preparation of nitrogen-containing activated carbons. the optimum technological conditions was as follows: the activation temperature was 700℃, the activation time was 2 h, the weight ratio of PANI to H3PO4 was 2:1, the heating rate was 7℃/min. The nitrogen-containing activated carbon by H3PO4 activation had good cycle performance, it had good current ratio performance and cycle life. Its specific capacitance retained 99% of original specific capacitance after 10,000 cycles.2. Nitrogen-containing activated carbons have been prepared from PANI by KOH activation for supercapacitors. L9 (34) orthogonal experiments were employed in finding the optimum technological conditions of the preparation of nitrogen-containing activated carbons. the optimum technological conditions was as follows: the activation temperature was 700℃, the activation time was 2 h, the weight ratio of PANI to KOH was 2:1, the heating rate was 7℃/min. The nitrogen-containing activated carbon by KOH activation had very high specific surface area, it was as high as 2287 m2/g, its specific capacitance was improved to 220 F/g. The effect of nitrogen atomic functionalities on the pseudocapacitive property has been studied, the experimental results have proved there are two mechanisms of energy storage in doped carbons: double layer formation and pseudocapacitance.3. The electrochemical performance of the unactivated carbon, H3PO4 activated carbon and KOH activated carbon as the anode materials of lithium ion batteries have been studied. The first discharge capacity of three carbons was much higher than the theoretical capacity of graphite. Among them, the first discharge capacity of KOH activated carbon was the highest, was 2201 mAh/g, it was attributed to its very high specific surface area. The first irreversible capacity of three carbons was very high, with the increasing number of cycles, the fading of capacity was fast. Among them, the fading of capacity of KOH activated carbon was the lowest, its charge capacity was 747 mAh/g after 20 cycles. |
