Towards fractional-order capacitors with broad tunable constant phase angles: multi-walled carbon nanotube-polymer composite as a case study

Abstract

In this study, multi-walled carbon nanotube (MWCNT) filled Polyevinelidenefluoride-trifluoroethylene-16 chlorofluoroethylene (PVDF-TrFE-CFE) composites are used to realize fractional-order capacitors (FOCs). A 17 solution-mixing and drop-casting approach is used to fabricate the composite. Due to the high aspect ratio of 18 MWCNTs, percolation regime starts at a small weight percentage (wt%), 1.00 % .The distributed MWCNTs inside 19 the polymer act as an electrical network of micro-capacitors and micro-resistors, which, in effect, behaves like a FOC. 20

Validation of Fractional-Order Lowpass Elliptic Responses of (1 + α)-Order Analog Filters

“…The specific resistors and capacitors are given in Table 1 when a frequency of ω 0 = (2π)10 krad/s is used. At this time, fractional-order capacitors are not available for either simulations or physical realizations and require the use of approximations; however, it is important to note the recent progress in realizing devices with fractional-order impedances [26][27][28]. For the simulations and experimental circuits in this work, the fractional-capacitors were approximated using the 5th order Foster-I topology given in Figure 12.…”

Fractional-Order Hartley Oscillator

“…Recently, different approaches to realization of fractionalorder elements (called constant phase elements in electrochemistry), particularly, fractional-order capacitors (FOCs) [9][10][11][12][13] have been developed. Among these approaches, those make use of composites of different materials have gained traction, since they lead to FOCs that can be easily integrated with microelectronics , and design an FOC with tunable constant phase angle (CPA) [9][10].…”

Solid state MXene based electrostatic fractional capacitors

“…There are several types of fractional order capacitors (0 < a < 1, À90 < u < 0) reported in the literature, including electrochemical capacitors, 19 fractal structures, 20 RC ladders, 21 CMOS-based emulators, 22,23 polymer dilectrics, 2 and composites. 1,24,25 Two-dimensional materials have attracted intense attention due to their promising potentials in electrical applications. 26 For the composite fractional order capacitors (FOCs), 2 in order to represent the response of a RC network, solid-state structures were used to realize FOCs by embedding two-dimensional nanosheets, i.e., reduced graphene oxide (rGO) 1 sheets or multiwalled carbon nanotubes (MWCNTs) 25 in the P(VDF)-based polymer matrix.…”

“…1,24,25 Two-dimensional materials have attracted intense attention due to their promising potentials in electrical applications. 26 For the composite fractional order capacitors (FOCs), 2 in order to represent the response of a RC network, solid-state structures were used to realize FOCs by embedding two-dimensional nanosheets, i.e., reduced graphene oxide (rGO) 1 sheets or multiwalled carbon nanotubes (MWCNTs) 25 in the P(VDF)-based polymer matrix. The magnitude of the constant phase angle (CPA) could be tuned by varying the filler volume.…”