Influence of the polymeric coating thickness on the electrochemical performance of Carbon Fiber/PAni composites

Abstract

SbstractCarbon fiber/polyaniline composites (CF/PAni) were synthesized at three different deposition time of 30, 60 and 90 min by oxidative polymerization. The composite materials were morphologically and physically characterized by scanning electron microscopy and by Raman spectroscopy, respectively. Their electrochemical responses were analyzed by cyclic voltammetry, by galvanostatic test, and by electrochemical impedance spectroscopy. The influence of the PAni layer thickness deposited on carbon fibers for the composite formation as well as for their electrochemical properties was discussed. The CF/PAni-30 showed a nanometric thickness with more homogeneous morphology compared to those formed in deposition times of 60 and 90 min. It also showed, from the electrochemical impedance spectroscopy measurements, the lowest charge transfer resistance value associated to the its highest value for the double-layer capacitance of 180 Fg -1 making it a very strong candidate as a supercapacitor electrode.

A Novel α‐MoO3/Single‐Walled Carbon Nanohorns Composite as High‐Performance Anode Material for Fast‐Charging Lithium‐Ion Battery

“…A decrease in the slope could be ascribed to either delamination of electrode material (degradation of mechanical properties of binder) or electrode cracking caused by the volume expansion (which causes breakdown the electrical contact percolation network of the electrode) or formation of secondary phases due to the higher localized charge density on the active material. [43][44][45] Hence, it is difficult to identify the key factors affecting the change in R CT and the slope of the line in the Nyquist plots. In this regard, an electrical equivalent circuit (EEC) consisting of an Ohmic resistance or solution resistance (R 0 ), film resistance (R SEI ), charge-transfer resistance (R CT ), constant phase element (CPE SEI and CPE CT ), and a closed Warburg impedance element (W 0 ) was constructed to fit the impedance data of all cells (Figure 9d).…”

Electrochemical Energy Storage Properties of Ni-Mn-Oxide Electrodes for Advance Asymmetric Supercapacitor Application

“…The porous nature of the electrode has an important contribution to the electrochemical charge storage process, which deviates from the performance of the pure capacitive behavior. However, for practical purpose, the capacitive performance of an electrode could be sensibly represented as CPE in parallel with R ct. , The fitted charge transfer parameters obtained from the equivalent circuit model are listed in Table . The R s values of Ni-Mn-oxides are 1.29, 0.99, 0.33, and 0.52 Ω, respectively, for Ni:Mn = 1:1, 1:2, 1:3, and 1:4, signifying their low resistance.…”

Síntese e caracterização do LiFePO4 dopado com Mn ou Co e seus compósitos com PDMcT/PAni para aplicação em dispositivos de armazenamento de energia

“…Nos gráficos de Bode (log | Z | vs. log f) e (-θ vs. vs. log f ) observa-se que os compósitos de PAni/PDMcT, LiFe0,9Mn0,1PO4/PAni e LiFe0,9Mn0,1PO4/PDMcT/PAni apresentaram comportamento capacitivo semelhante ao da PAni, o que é evidenciado pelo ângulo de fase próximo a 90° (Figura 40). Além disso, a partir destes diagramas de Bode foi possível verificar que o armazenamento de carga ocorre em baixas frequências, relacionadas ao acúmulo de carga na maior parte do eletrodo (capacitância limite) (CANOBRE et al, 2009;FONSECA et al, 2015).…”

“…Para os cálculos de capacitância limite dos compósitos binários e ternário, considerou-se a frequência de 0,1 Hz e os respectivos valores de -Z" (Tabela 13). A capacitância limite está associada a saturação de carga na superfície do eletrodo devido ao processo pseudocapacitivo da PAni, no qual ocorre a entrada e saída de contra íons da matriz polimérica (FONSECA, et al, 2015). Como citado anteriormente, o CPE é o elemento de fase constante e é utilizado ao invés de capacitância pura, especialmente em materiais porosos e rugosos, como é o caso dos compósitos poliméricos.…”