Performance of printable supercapacitors in an RF energy harvesting circuit

Lehtimäki, Suvi; Li, Miao; Salomaa, Jarno; Pörhönen, Juho; Kalanti, Antti; Tuukkanen, Sampo; Heljo, Petri; Halonen, K.; Lupo, Donald

doi:10.1016/j.ijepes.2014.01.004

Cited by 62 publications

(28 citation statements)

References 17 publications

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“…The ESR is large compared to devices using metallic current collectors, but is still in a range which is usable in applications where the currents needed are small, e.g. < 1 mA, such as distributed sensors10.…”

Section: Resultsmentioning

confidence: 99%

“…Particularly, systems using micropower energy harvesting from ambient light, vibrations, or other sources, require intermediate energy storage for continuous operation. Supercapacitors are well suited to such applications due to their high cycle life and the possibility of preparing them with safe and non-toxic materials910.…”

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confidence: 99%

“…Screen-printed electrodes have been previously prepared from activated carbon711 as well as pseudocapacitive graphene composites1213. Bar-coating5614, blade-coating101516 and dispenser printing49 have also been used for preparing thick supercapacitor electrodes. As the capacitance depends directly on the thickness of the active layer, it is important to be able to print layers reliably.…”

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confidence: 99%

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Performance, stability and operation voltage optimization of screen-printed aqueous supercapacitors

Lehtimäki

Railanmaa

Keskinen

et al. 2017

Sci Rep

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Harvesting micropower energy from the ambient environment requires an intermediate energy storage, for which printed aqueous supercapacitors are well suited due to their low cost and environmental friendliness. In this work, a systematic study of a large set of devices is used to investigate the effect of process variability and operating voltage on the performance and stability of screen printed aqueous supercapacitors. The current collectors and active layers are printed with graphite and activated carbon inks, respectively, and aqueous NaCl used as the electrolyte. The devices are characterized through galvanostatic discharge measurements for quantitative determination of capacitance and equivalent series resistance (ESR), as well as impedance spectroscopy for a detailed study of the factors contributing to ESR. The capacitances are 200–360 mF and the ESRs 7.9–12.7 Ω, depending on the layer thicknesses. The ESR is found to be dominated by the resistance of the graphite current collectors and is compatible with applications in low-power distributed electronics. The effects of different operating voltages on the capacitance, leakage and aging rate of the supercapacitors are tested, and 1.0 V found to be the optimal choice for using the devices in energy harvesting applications.

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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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Performance, stability and operation voltage optimization of screen-printed aqueous supercapacitors

Lehtimäki

Railanmaa

Keskinen

et al. 2017

Sci Rep

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“…Conductive carbon materials, in particular those derived from graphite and carbon black, have been used in the manufacture of inks and coatings for a range of printed electronic applications including batteries [1] and supercapacitors [2,3], electrochemical sensors [4], PCB resistors [5] printed heaters [6] and more recently in solar energy harvesting [7]. Carbon inks have a host of favourable characteristics that allow them to be used in these applications, including chemical inertness, the ability to be modified or functionalised in the case of electrochemical sensors and ability to act as intercalating materials in the case of energy storage, as well as low cost and disposability.…”

Section: Introductionmentioning

confidence: 99%

The effect of graphite and carbon black ratios on conductive ink performance

et al. 2017

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Conductive inks based on graphite and carbon black are used in a host of applications including energy storage, energy harvesting, electrochemical sensors and printed heaters. This requires accurate control of electrical properties tailored to the application; ink formulation is a fundamental element of this. Data on how formulation relates to properties have tended to apply to only single types of conductor at any time, with data on mixed types of carbon only empirical thus far. Therefore, screen printable carbon inks with differing graphite, carbon black and vinyl polymer content were formulated and printed to establish the effect on rheology, deposition and conductivity. The study found that at a higher total carbon loading ink of 29.4% by mass, optimal conductivity (0.029 X cm) was achieved at a graphite to carbon black ratio of 2.6 to 1. For a lower total carbon loading (21.7 mass %), this ratio was reduced to 1.8 to 1. Formulation affected viscosity and hence ink transfer and also surface roughness due to retention of features from the screen printing mesh and the inherent roughness of the carbon components, as well as the ability of features to be reproduced consistently.

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“…The commercially available ECs are characterized by a high life cycle of more than 1 000 000 charge/discharge cycles [30]. Since EDLCs can deliver all the stored energy within around 5 s, they can be used as energy storage and power deliverers for many applications, for example, electric and hybrid vehicles, tramways, buses, cranes, forklifts, wind turbines, electricity load leveling in stationary and transportation systems, opening emergency doors of aircrafts, diesel engines, and renewable energy harvesting [28,31].…”

Section: Fundamentals On Carbon/carbon Electrical Double-layer Capacimentioning

confidence: 99%