聚吡咯包裹碳化硅气凝胶复合材料的电化学和吸波性能

Electrochemical and Microwave Absorbing Properties of Polypyrrole Coated Silicon Carbide Aerogel Composites

聚吡咯(polypyrrole,PPy)由于具有高比电容、高电导率、高柔韧性和结构多样性而被用作超级电容器的电极材料,而且可以与其他材料复合,能够提高介电损耗从而提高吸波性能。采用化学原位聚合法,合成了PPy包覆SiC气凝胶复合材料,有效解决了PPy在充放电过程中因离子的掺杂和去掺杂而变得不稳定,导致PPy基超级电容器循环稳定性下降等问题。用三电极体系测试复合材料的电化学性能,用矢量网络分析仪进行电磁参数测试。结果表明,在0.5 A·g^(-1)的电流密度下比电容达309.65F·g^(-1),在1000次循环后比电容保持率为94.2%,具有良好的循环稳定性;气凝胶经历了100次砝码的反复压能保持95%的高度,抗压强度可达105 kPa;在2.2 GHz的有效吸收强度为22.32 dB,而PPy只有8.99 dB,有效提高了吸收强度。因此,SiC/PPy复合材料是很有应用前景的超级电容器电极材料和电磁波吸收材料。

Polypyrrole(PPy)is used as an electrode material for supercapacitors due to its high specific capacitance,high conductivity,high flexibility and structural diversity.It can be compounded with other materials to improve dielectric loss and absorption performance.PPy-coated silicon carbide(SiC)aerogel composites were synthesized by chemical in-situ polymerization,which effectively solved the problems of the decline of cycle stability of PPy-based supercapacitors induced by the ion doping/dedoping during the charging/discharging process.The electrochemical performance of the composite material was measured by the three-electrode system,and the electromagnetic parameters were tested with the vector network analyzer.The results show that the specific capacitance reaches 309.65 F·g^(-1)at a current density of 0.5A·g^(-1),and the specific capacitance retention rate is 94.2%after 1000 cycles,indicating good cycle stability.The aerogel can maintain a height of 95%subjected to 100 repeated pressure.The compressive strength is 105 kPa.The effective absorption intensity at 2.2 GHz is 22.32 dB,while the value for PPy is only 8.99 dB,which effectively improve absorption intensity.Therefore,SiC/PPy composites are promising electrode materials for supercapacitors and electromagnetic wave absorbing materials.