Scalable fabrication of ultrathin free-standing graphene nanomesh films for flexible ultrafast electrochemical capacitors with AC line-filtering performance
“…12b). Meanwhile, the τ RC of the AHEC is better than most aqueous ECs and over 40 times shorter than the required period of 8.3 ms for 120 Hz filtering (Supplementary Table 1) 12,14–16,18,25–31 . Such a small τ RC demonstrates the highly efficient reduction of charging/discharging time for fast AC-line filtering ability at 120 Hz 32 .Fig.…”
Section: Resultsmentioning
confidence: 97%
“…d Plots of areal specific capacitance ( C A ) as a function of frequency. e Comparison of E A and voltage window of the aqueous hybrid electrochemical capacitor (AHEC) with those of the reported aqueous AC-line filtering electrochemical capacitors (ECs) (Supplementary Table 1) 12,14–16,18,25–31 . f Cycling stability and the Coulombic efficiency of the AHECs at a current density of 5 mA cm −2 for 10,000 cycles.…”
Filtering capacitor is a necessary component in the modern electronic circuit. Traditional filtering capacitor is often limited by its bulky and rigid configuration and narrow workable scope of applications. Here, an aqueous hybrid electrochemical capacitor is developed for alternating current line filtering with an applicable wide frequency range from 1 to 10,000 Hz. This capacitor possesses an areal specific energy density of 438 μF V
2
cm
−2
at 120 Hz, which to the best of our knowledge is record high among aqueous electrochemical capacitors reported so far. It can convert arbitrary alternating current waveforms and even noises to straight signals. After integration of capacitor units, a workable voltage up to hundreds of volts (e.g., 200 V) could be achieved without sacrificing its filtering capability. The integrated features of wide frequency range and high workable voltage for this capacitor present promise for multi-scenario and applicable filtering capacitors of practical importance.
“…12b). Meanwhile, the τ RC of the AHEC is better than most aqueous ECs and over 40 times shorter than the required period of 8.3 ms for 120 Hz filtering (Supplementary Table 1) 12,14–16,18,25–31 . Such a small τ RC demonstrates the highly efficient reduction of charging/discharging time for fast AC-line filtering ability at 120 Hz 32 .Fig.…”
Section: Resultsmentioning
confidence: 97%
“…d Plots of areal specific capacitance ( C A ) as a function of frequency. e Comparison of E A and voltage window of the aqueous hybrid electrochemical capacitor (AHEC) with those of the reported aqueous AC-line filtering electrochemical capacitors (ECs) (Supplementary Table 1) 12,14–16,18,25–31 . f Cycling stability and the Coulombic efficiency of the AHECs at a current density of 5 mA cm −2 for 10,000 cycles.…”
Filtering capacitor is a necessary component in the modern electronic circuit. Traditional filtering capacitor is often limited by its bulky and rigid configuration and narrow workable scope of applications. Here, an aqueous hybrid electrochemical capacitor is developed for alternating current line filtering with an applicable wide frequency range from 1 to 10,000 Hz. This capacitor possesses an areal specific energy density of 438 μF V
2
cm
−2
at 120 Hz, which to the best of our knowledge is record high among aqueous electrochemical capacitors reported so far. It can convert arbitrary alternating current waveforms and even noises to straight signals. After integration of capacitor units, a workable voltage up to hundreds of volts (e.g., 200 V) could be achieved without sacrificing its filtering capability. The integrated features of wide frequency range and high workable voltage for this capacitor present promise for multi-scenario and applicable filtering capacitors of practical importance.
“…Furthermore, there is no significant observation of satellite peak at Cu2p 3/2 region, reflects the formation of Cu 3 NÀ Cu 3 P heterostructure with absence of Cu + and Cu 2 + states, strongly indicates that resultant heterostructure is protected by ultrathin carbon layer on the surface prevents from surface oxidation. [60,61] In the C 1s spectra (Figure 3b), the main peak at roughly 284.8 eV can be attributed to CÀ C/C=C bond, while the heteroatoms (nitrogen, phosphorus, and sulfur) bonded carbon are centered at 285.5 (CÀ P/CÀ OÀ P) and 286.3 eV (CÀ N/C=N/CÀ S), respectively, [61][62][63][64] indicating that both N, S and P atoms are doped in the carbon in Cu 3 NÀ Cu 3 P/NPSC. In addition, the peak located at high binding energy (287.6 eV) can be assigned to the C=O groups.…”
Section: Fabrication and Characterization Sectionmentioning
Efficient and robust electrocatalysts composed of earth‐abundant elements to replace noble metals is highly essential for cost‐effective production of hydrogen from water splitting. Herein, we demonstrate the fabrication of SO42− anions bridged MOF‐derived Cu3N−Cu3P heterostructure coated by ultrathin N, P, S‐tri‐doped carbon (NPSC) on nickel foam (Cu3N−Cu3P/NPSCNWs@NF) via an interface reconstruction strategy. The first‐principle simulation demonstrates that both Cu3N, Cu3P and NPSC own good electrical conductivity, suggesting these species can lead to efficient electrocatalytic performance. The remarkable features of high intrinsic conductivity and interfacial heterostructures at Cu3N−Cu3P/NPSCNWs@NF have ensured excellent water splitting electrocatalytic activity with a low potential of 1.54 V at 10 mA cm−2 in 1 M KOH over 24 h, and additionally the resultant electrode exhibits impressive response for HER with an ultralow potential of 109 mV at 10 mA cm−2 in neutral‐pH media over 30 h.
“…1−6 In energy-storage system, supercapacitors play a major role as they have high power density, long life cycle, cost-effectiveness, and eco-friendly properties compared to batteries. 7−10 Based on the mechanism of energy storage, supercapacitors are categorized as pseudocapacitors and electric double-layer capacitors (EDLC). Pseudocapacitors involve reversible redox or faradic charge-transfer reactions and use transition-metal oxides 11,12 and conducting polymers as electrodes.…”
Mesoporous carbon spheres (MCS-750,
MCS-800, MCS-850, MCS-900,
and MCS-950) have been synthesized by a facile strategy with low temperature
and rapid chemical vapor deposition technique. The synthesized MCS
possess relatively large surface area (570–670 m
2
g
–1
), good graphitization, remarkable porosity,
and redox functionalities on the surface of the synthesized MCS. Combination
of these structural and surface properties of the synthesized MCS
as an electrode material (MCS-850) showed an excellent charge-storage
capacity with a specific capacitance of 338 F/g at 1 mV/s, 217 F/g
at 0.5 A/g. MCS-850 shows long-term cycling stability with capacitive
retention of more than 96% after 2000 cycles in 6 M KOH electrolyte.
In addition, a fabricated two-electrode symmetric cell obtained 86%
retention after 2000 cycles. The two-electrode symmetric device exhibited
a specific capacitance of 63 F/g at 5 mV/s with an energy density
of 7.1 Wh/kg.
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