Synthesis and electrochemical evaluation of the PANI/δ-MnO2 electrode for high performing asymmetric supercapacitors
Synthesis and electrochemical evaluation of the PANI/δ-MnO2 electrode for high performing asymmetric supercapacitors
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DOI：
10.1039/c7nj00679a
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发表时间：
2017-07
影响因子：
3.3
通讯作者：
I. I. Misnon-I.;R. Jose
中科院分区：
文献类型：
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作者：
I. I. Misnon-I.;R. Jose
本文全面分析了聚苯胺（PANI）原位聚合对水热合成的birnessite型MnO2 （δ-MnO2）花的结构、表面、形态和电化学性能的影响。PANI-MnO2电极的比电容比纯MnO2电极高约170%；系统地研究和讨论了促进这种增强的因素。聚苯胺改性使二氧化锰的非活性表面具有电化学活性，降低了特征电阻和电荷弛豫时间。此外，PANI改性提高了复合材料的电导率，导致(i)表面伪电容从87% （MnO2）降低到54% (PANI - MnO2), （ii）活性电荷贡献从42% （MnO2）提高到46% （PANI - MnO2）。讨论了这些变化的机理。此外，在纽扣电池外壳中制备了不对称（PANI-MnO2 //AC和PANI-MnO2 //OMC）和对称（AC//AC和OMC//OMC）（其中AC为活性炭，OMC为介孔碳）超级电容器，并评估了它们的电荷存储性能。能源储存显著增加；然而，它们的性能根据碳电极的孔隙率而变化。本研究的结果为非对称超级电容器中不同碳选择的聚合物涂覆金属氧化物电极的电荷存储行为提供了更好的理解。
A comprehensive analysis of the effect of in situ polymerization of polyaniline (PANI) on hydrothermally synthesized Birnessite-type MnO2 (δ-MnO2) flowers on the structural, surface, morphological, and electrochemical properties is presented in this article. The PANI–MnO2 electrodes showed ∼170% higher specific capacitance than pure MnO2; the factors contributing to this enhancement are systematically investigated and discussed. The PANI modification enabled the inactive surface of the MnO2 to be electrochemically active and reduced the characteristic resistances and charge relaxation time. Furthermore, the PANI modification improved the composite conductivity and resulted in (i) reduction of surface pseudocapacitance from 87% (MnO2) to 54% (PANI–MnO2) and (ii) improvement of active charge contribution from 42% (MnO2) to 46% (PANI–MnO2). The mechanism of these changes is discussed. Furthermore, asymmetric (PANI–MnO2//AC and PANI–MnO2//OMC) and symmetric (AC//AC and OMC//OMC) (where AC is activated carbon and OMC is mesoporous carbon) supercapacitors are fabricated in coin cell casing and their charge storage properties are evaluated. Impressive increase in energy storage is observed; however, their properties varied according to the porosity of the carbon electrode. Results from this study provide a better understanding of the charge storage behaviour of polymer coated metal oxide electrodes with a varied choice of carbons in asymmetric supercapacitors.