Covalently Linked Polyoxometalate-Polypyrrole Hybrids: Electropolymer Materials with Dual-Mode Enhanced Capacitive Energy Storage
Covalently Linked Polyoxometalate-Polypyrrole Hybrids: Electropolymer Materials with Dual-Mode Enhanced Capacitive Energy Storage
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DOI：
10.1021/acs.macromol.0c02354
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发表时间：
2020-12-22
期刊：
影响因子：
5.5
通讯作者：
Fielden, John
中科院分区：
文献类型：
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作者：
Alshehri, Sarah A.;Al-Yasari, Ahmed;Fielden, John
Lindqvist型聚氧乙烯酸酯（POM）通过芳基-亚氨基键[Mo 6 O 18 NPhPy]（2-）（1）和[Mo 6 O 18 NPhCCPhPy]（2-）（2）与吡咯（Py）进行共电聚合，产生第一种具有共价连接的POM“分子金属氧化物”的电聚合物膜。X-射线光电子能谱（XPS）和能量色散X-射线（EDX）元素分析表明，实现的POM的负载量远远高于传统的，非共价包合膜，和共价连接防止损失的POM在初始还原循环。循环伏安法、电化学阻抗谱和恒电流充放电测量一起表明，POM通过改变聚吡咯（PPy）膜的行为和通过POM氧化还原过程引入大量额外的法拉第贡献来提高比电容（高达5倍）并降低膜的电荷转移电阻。增加POM-PPy连接体的长度改善了电容和稳定性，PPy 2在1200次循环中保持其初始电容的95%。
Lindqvist-type polyoxometalates (POMs) derivatized with pyrrole (Py) via an aryl-imido linkage [Mo6O18NPhPy](2-) (1) and [Mo6O18NPhCCPhPy](2-) (2) undergo coelectropolymerization with pyrrole, producing the first electropolymer films with covalently attached POM "molecular metal oxides". X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray (EDX) elemental analyses indicate that the loadings of POM achieved are far higher than in conventional, noncovalent inclusion films, and covalent attachment prevents loss of POM on initial reduction cycles. Cyclic voltammetry, electro- chemical impedance spectroscopy, and galvanostatic charge-discharge measurements together indicate that the POMs enhance the specific capacitance (up to 5x) and decrease the charge-transfer resistance of the films by both modifying the behavior of the polypyrrole (PPy) film and introducing a substantial additional faradaic contribution through the POM redox processes. Increasing the length of the POM-PPy linker improves both capacitance and stability, with PPy 2 retaining 95% of its initial capacitance over 1200 cycles.