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Alternating current line-filter based on electrochemical capacitor utilizing template-patterned graphene.

Wu Z, Li L, Lin Z, Song B, Li Z, Moon KS, Wong CP, Bai SL - Sci Rep (2015)

Bottom Line: In this work, graphene oxide (GO) is reduced by patterned metal interdigits at room temperature and used directly as the electrode material.In addition, it retains 97.2% of the initial capacitance after 10000 charge/discharge cycles.These outstanding performance characteristics of our device demonstrate its promising to replace the conventional AECs for ac line filtering.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Materials Science and Engineering, CAPT/HEDPS/LTCS, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, College of Engineering, Peking University, Beijing 100871, China [2] School of Material Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0245, USA.

ABSTRACT
Aluminum electrolytic capacitors (AECs) are widely used for alternating current (ac) line-filtering. However, their bulky size is becoming more and more incompatible with the rapid development of portable electronics. Here we report a scalable process to fabricate miniaturized graphene-based ac line-filters on flexible substrates at room temperature. In this work, graphene oxide (GO) is reduced by patterned metal interdigits at room temperature and used directly as the electrode material. The as-fabricated device shows a phase angle of -75.4° at 120 Hz with a specific capacitance of 316 µF/cm(2) and a RC time constant of 0.35 ms. In addition, it retains 97.2% of the initial capacitance after 10000 charge/discharge cycles. These outstanding performance characteristics of our device demonstrate its promising to replace the conventional AECs for ac line filtering.

No MeSH data available.


(a) The variation of real and imaginary part of capacitance versus frequency.b) Capacitance versus frequency.
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f4: (a) The variation of real and imaginary part of capacitance versus frequency.b) Capacitance versus frequency.

Mentions: The outstanding performance is further supported with the ultra-small relaxation time constant (τ0). τ0 reflects the minimum time needed to discharge all the energy from the device with an efficiency of greater than 50%, which can be obtained from the frequency at a maximum imaginary capacitance (C”)141531. Figure 4(a) shows an extremely small τ0 of 1.9 ms for the as-fabricated ac line-filter. Meanwhile, a series RC circuit model, also known as Randles circuit model, is employed to simulate the capacitive and resistive components of the device. The specific areal capacitance is calculated based on the equation of , in which f is the frequency, A is the area of the device and Z” is the imaginary part of the impedance31. Figure 4(b) presents the frequency response specific areal capacitance, which reaches 316 μF/cm2 at 120 Hz and maintains capacitive behavior up to 104 Hz. The resistance at 120 Hz is 7.5 Ω, which corresponds to a RC time constant τRC of 0.35 ms considering an electrode area of 14.88 mm2 of the device. This value is comparable to those reported with vertical graphene EDLC (0.20 ms)13, graphene/VACNT hybrids (0.20 ~ 0.40 ms)14 and electrochemically reduced GO (1.35 ms)15. It is also significantly smaller than the required 8.3 ms for 120 Hz filtering.


Alternating current line-filter based on electrochemical capacitor utilizing template-patterned graphene.

Wu Z, Li L, Lin Z, Song B, Li Z, Moon KS, Wong CP, Bai SL - Sci Rep (2015)

(a) The variation of real and imaginary part of capacitance versus frequency.b) Capacitance versus frequency.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4470326&req=5

f4: (a) The variation of real and imaginary part of capacitance versus frequency.b) Capacitance versus frequency.
Mentions: The outstanding performance is further supported with the ultra-small relaxation time constant (τ0). τ0 reflects the minimum time needed to discharge all the energy from the device with an efficiency of greater than 50%, which can be obtained from the frequency at a maximum imaginary capacitance (C”)141531. Figure 4(a) shows an extremely small τ0 of 1.9 ms for the as-fabricated ac line-filter. Meanwhile, a series RC circuit model, also known as Randles circuit model, is employed to simulate the capacitive and resistive components of the device. The specific areal capacitance is calculated based on the equation of , in which f is the frequency, A is the area of the device and Z” is the imaginary part of the impedance31. Figure 4(b) presents the frequency response specific areal capacitance, which reaches 316 μF/cm2 at 120 Hz and maintains capacitive behavior up to 104 Hz. The resistance at 120 Hz is 7.5 Ω, which corresponds to a RC time constant τRC of 0.35 ms considering an electrode area of 14.88 mm2 of the device. This value is comparable to those reported with vertical graphene EDLC (0.20 ms)13, graphene/VACNT hybrids (0.20 ~ 0.40 ms)14 and electrochemically reduced GO (1.35 ms)15. It is also significantly smaller than the required 8.3 ms for 120 Hz filtering.

Bottom Line: In this work, graphene oxide (GO) is reduced by patterned metal interdigits at room temperature and used directly as the electrode material.In addition, it retains 97.2% of the initial capacitance after 10000 charge/discharge cycles.These outstanding performance characteristics of our device demonstrate its promising to replace the conventional AECs for ac line filtering.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Materials Science and Engineering, CAPT/HEDPS/LTCS, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, College of Engineering, Peking University, Beijing 100871, China [2] School of Material Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0245, USA.

ABSTRACT
Aluminum electrolytic capacitors (AECs) are widely used for alternating current (ac) line-filtering. However, their bulky size is becoming more and more incompatible with the rapid development of portable electronics. Here we report a scalable process to fabricate miniaturized graphene-based ac line-filters on flexible substrates at room temperature. In this work, graphene oxide (GO) is reduced by patterned metal interdigits at room temperature and used directly as the electrode material. The as-fabricated device shows a phase angle of -75.4° at 120 Hz with a specific capacitance of 316 µF/cm(2) and a RC time constant of 0.35 ms. In addition, it retains 97.2% of the initial capacitance after 10000 charge/discharge cycles. These outstanding performance characteristics of our device demonstrate its promising to replace the conventional AECs for ac line filtering.

No MeSH data available.