Reaction of Aniline with FeOCl. Formation and Ordering of Conducting Polyaniline in a Crystalline Layered Host

Wu, Chun‐Guey; DeGroot, Donald C.; Marcy, Henry O.; Schindler, J. L.; Kannewurf, Carl R.; Bakas, Thomas; Papaefthymiou, V.; Hirpo, Wakgari; Yesinowski, James P.; Liu, Y.-J.; Kanatzidis, Mercouri G.

doi:10.1021/ja00141a015

Cited by 145 publications

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“…Our value of the Fe 2+ fraction is about twice as large as the estimates based on Mössbauer spectroscopy for different guests and various intercalation stoichiometries between 0.05 and 0.36. [6][7][8][9][10][11] It is well known that the host-matrix charge transfer corresponds to an electron hopping mechanism with a time scale on par with that of the Mössbauer effect (∼ 10 −8 s). [6][7][8] Since this is a thermally-activated process, the fraction of Fe 2+ and Fe 3+ sites that are undistinguishable and appear as a mixed-valence component in the Mössbauer spectrum increases with temperature.…”

Section: Degree Of Charge Transfer: Discussionmentioning

confidence: 99%

“…[6][7][8] Since this is a thermally-activated process, the fraction of Fe 2+ and Fe 3+ sites that are undistinguishable and appear as a mixed-valence component in the Mössbauer spectrum increases with temperature. Accordingly, the previously reported Fe 2+ fractions were estimated using the spectrum collected at the lowest possible temperature, just before the onset of antiferromagnetism near T N =65 K. [6][7][8][9][10][11] Below this temperature, the magnetic order splits the spectral lines into unresolved sextets, thereby precluding any quantitative determination of the Fe 2+ /Fe 3+ ratio. It is however likely that the spectra collected just above T N are still affected by the electron-hopping relaxation time, resulting in lower Fe 2+ fractions.…”

Section: Degree Of Charge Transfer: Discussionmentioning

confidence: 99%

“…33 PANI intercalation results in a p-type semiconductor behavior and a substantial increase in the conductivity in the order of 10 5 ∼ 10 6 Ω −1 .cm −1 . 11,34 The fact that the conductivity of the intercalated FeOCl systems is governed by the 3d electron hopping mechanism in the partially reduced FeOCl layers 5 suggests that increasing the extent of charge transfer between the guest and the host could enhance the conductivity. One may instinctively expect the charge transfer to increase with increasing the host-guest interaction.…”

Section: High Pressurementioning

confidence: 99%

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Charge transfer in FeOCl intercalation compounds and its pressure dependence: An x-ray spectroscopic study

et al. 2010

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We present a study of charge transfer in Na-intercalated FeOCl and polyaniline-intercalated FeOCl using high-resolution x-ray absorption spectroscopy and resonant x-ray emission spectroscopy at the Fe-K edge. By comparing the experimental data with ab-initio simulations, we are able to unambiguously distinguish the spectral changes which appear due to intercalation into those of electronic origin and those of structural origin. For both systems, we find that about 25% of the Fe sites are reduced to Fe 2+ via charge transfer between FeOCl and the intercalate. This is about twice as large as the Fe 2+ fraction reported in studies using Mössbauer spectroscopy. This discrepancy is ascribed to the fact that the charge transfer occurs on the same time scale as the Mössbauer effect itself. Our result suggests that every intercalated atom or molecule is involved in the chargetransfer process, thus making this process a prerequisite for intercalation. The Fe 2+ fraction is found to increase with pressure for polyaniline-FeOCl, hinting at an enhancement of the conductivity in the FeOCl intercalation compounds under pressure.

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Section: Degree Of Charge Transfer: Discussionmentioning

confidence: 99%

Section: Degree Of Charge Transfer: Discussionmentioning

confidence: 99%

Section: High Pressurementioning

confidence: 99%

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Charge transfer in FeOCl intercalation compounds and its pressure dependence: An x-ray spectroscopic study

et al. 2010

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“…1,2 The two-dimensional (2-D) frameworks are typical of layered inorganic solids such as transition-metal oxides (V 2 O 5 , MoO 3 ), dichalcogenides (MoS 2 ), oxyhalides (FeOCl), halides (a-RuCl 3 ), phosphates (Zr(HPO 4 ) 2 , VOPO 4 ), mica-type layered silicates (2 : 1 layered silicates, smectite clays) as well as layered double hydroxides (LDHs). [3][4][5][6][7][8][9][10][11][12][13][14][15] Among such 2-D inorganic materials, the layered silicates are the most common 2-D solids and their unique characteristics, such as high aspect ratio as well as high surface area, make an important contribution to novel properties of nanocomposites. 16,17 Layered silicates such as montmorillonites and hectorites possess the same structural characteristics as the well-known talc and mica.…”

Section: Introductionmentioning

confidence: 99%

Structural changes of polyaniline/montmorillonite nanocomposites and their effects on physical properties

et al. 2003

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Polyaniline/montmorillonite (MMT) nanocomposites containing different PANI contents were prepared by the intercalation of aniline monomer into pristine MMT followed by the subsequent oxidative polymerization of the aniline in the interlayer spacings. The polyaniline/MMT nanocomposite structure intercalated with polyaniline (PANI) was examined by X-ray diffraction (XRD) and transmission electron microscopy (TEM). From the full-width at half-maximum (FWHM) of the (001) reflection peaks in the XRD patterns, the PANI/ MMT nanocomposite containing 12.3 wt% PANI (PMN12) was found to be in the most disordered state. The physical interaction between the intercalated PANI and the basal surfaces of MMT was monitored by FT-IR. The room-temperature conductivity (s RT ) varied from 9.1 6 10 29 to 1.5 6 10 0 S cm 21 depending on the PANI content in the nanocomposites. The temperature dependence of dc conductivity (s dc (T)) of all the samples follows the quasi-1D variable range hopping (quasi-1D VRH) model (i.e., s dc (T) 3 exp [2(T 0 /T) 1/2 ]). The charge transport behavior of this system was interpreted from the slopes (T 0 ) of the s dc curves and the highest T 0 value was found for the PANI/MMT nanocomposite with 12.3 wt% PANI (PMN12). The FT-IR, s dc (T) and s RT results for the nanocomposites with varying content of PANI are consistently related to the structure of the PANI/MMT nanocomposites discussed in the XRD analysis. The structural argument was further supported by scanning electron microscopy (SEM) of all the samples. Thermogravimetric analysis (TGA) showed improved thermal stability for the intercalated nanocomposites in comparison with the pure PANI and a simple PANI/MMT mixture.

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“…Em 1987, foi obtido o primeiro nanocompósito envolvendo PCE em um material bidimensional, onde o PPy foi inserido nas lamelas 181,182 . Esses materiais apresentaram uma condutividade elétrica superior a outros compostos de intercalação envolvendo o composto inorgânico, em razão da presença do polímero condutor eletrônico.…”

Section: Compósitos Entre Materiais Orgânicos E Inorgânicosunclassified

Materiais para cátodos de baterias secundárias de lítio

Varela¹,

Huguenin²,

Malta³

et al. 2002

Quím. Nova

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Recebido em 21/12/00; aceito em 4/7/01 MATERIALS FOR CATHODES OF SECONDARY LITHIUM BATTERIES. In this work, cathodes employed in secondary lithium batteries are reviewed. These cathodes have great technologic and scientific importance, specifically, materials for cathodes as electronic conductor polymers (ECP), transition metal oxides (TMO) and nanocomposites of ECP/TMO. The use of a specific cathodic material is based in some intrinsic characteristics that improve the performance of the battery. Thus, some vantages and disvantages of these insertion compounds are discussed, as lithium insertion capacity, energy density, and the ciclability of these materials.Keywords: secondary lithium batteries; cathodic materials; transition metal oxides; electronic conducting polymers; nanocomposites. INTRODUÇÃOUma fonte eletroquímica de potência ou bateria pode ser definida como um dispositivo capaz de converter diretamente a energia liberada numa reação química em energia elétrica. As baterias apresentam basicamente duas funções principais, a primeira é agir como fontes portáteis de potência elétrica. A segunda, que tem crescido em importância nos últimos trinta anos, está baseada na habilidade de certos sistemas eletroquímicos de armazenar a energia suprida por uma fonte externa. Tais baterias são utilizadas, em veículos elé-tricos, fontes de emergência, como parte de um sistema de fornecimento de curta duração para demandas em pico e em conjunção com fontes renováveis de energia, como solar ou eólica, por exemplo.A primeira descrição de uma bateria eletroquímica foi feita pelo italiano Alessandro Volta em 1800. Tal "descoberta" representa o marco na história da eletroquímica e, particularmente, na história dos dispositivos denominados genericamente baterias. Desde então, um notável progresso tem sido feito na área de armazenamento eletroquímico de energia. Hoje, pode-se enumerar uma grande variedade de dispositivos englobados na categoria de baterias: células metal-ar, metal-hidreto metálico (Ni-HM), níquel-cádmio (Ni-Cd), células térmicas, íons-Lítio, entre outras.O mercado para dispositivos primários consiste basicamente na produção de baterias para aparelhos portáteis. As baterias secundá-rias ou recarregáveis representam maior interesse devido à grande demanda atual de aparelhos celulares e microcomputadores portá-teis. Em 1997, por exemplo, dos 34 bilhões de dólares movimentados com baterias, 24 foram destinados às baterias secundárias 1 .Graças à simplicidade e reversibilidade das reações eletroquímicas de inserção ou intercalação, a grande maioria dos dispositivos secundários que operam à temperatura ambiente é baseada nos chamados eletrodos de inserção. Como exemplos, têm-se os dispositivos secundários aquosos, como hidreto metálico/NiOOH ou Zn/MnO 2 , que envolvem a inserção de H + no hidreto metálico 2,3 ou MnO 2 4,5. Até mesmo o mecanismo de redução do eletrodo positivo das baterias de chumbo ácido, PbO 2 6,7 pode ser atribuído ao processo de inserção de H + 8 .Considerando-se a utilização de cátions metálicos...

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Reaction of Aniline with FeOCl. Formation and Ordering of Conducting Polyaniline in a Crystalline Layered Host

Cited by 145 publications

References 1 publication

Charge transfer in FeOCl intercalation compounds and its pressure dependence: An x-ray spectroscopic study

Charge transfer in FeOCl intercalation compounds and its pressure dependence: An x-ray spectroscopic study

Structural changes of polyaniline/montmorillonite nanocomposites and their effects on physical properties

Materiais para cátodos de baterias secundárias de lítio

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