Comparison of commercial supercapacitors and high-power lithium-ion batteries for power-assist applications in hybrid electric vehicles I. Initial characterization

Chu, Andrew; Braatz, P. O.

doi:10.1016/s0378-7753(02)00364-6

Cited by 343 publications

(158 citation statements)

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“…Co/C composite fibers with diameters from 100 to 300 nm were found to exhibit a high reversible capacity of over 750 mAh/g and good rate capability of 678 mAh/g at 1 C. 62 These improvements, compared to the LIB performance of pure carbon fibers, were ascribed to the incorporation of cobalt that led to an increase in the interfacial surface area between carbon and liquid electrolyte as well as an enhanced electronic conductivity. F/g cell), 85 Generally the weight of the active material accounts for approximately 10% of the total cell mass for supercapacitor devices, and thus the gravimetric capacitance of commercial supercapacitors with respect to the mass of the active material is ~ 100 F/g.…”

Section: Electrospun Carbon Nanofibers As Anode Materials For Lithiummentioning

confidence: 99%

A Review of Electrospun Carbon Fibers as Electrode Materials for Energy Storage

Mao¹,

Hatton²,

Rutledge³

2013

COC

133

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Abstract:The applications of electrospun carbon fiber webs to the development of energy storages devices, including both supercapacitors and lithium ion batteries (LIB), are reviewed.Following a brief discussion of the fabrication process and characterization methods for ultrafine electrospun carbon fibers, recent advances in their performance as supercapacitors and LIBs anode materials are summarized. Optimization of the overall electrochemical properties of these materials through choice of thermal treatment conditions, incorporation of additional active components (such as carbon nanotubes, metal oxides, and catalysts), and generation of novel fibrous structures (such as core-shell, multi-channel or porous fibers) is highlighted. Further challenges related to improving the conductivity, surface area, and mechanical properties of the carbon nanofiber webs, as well as the scale-up ability of the fabrication technique, are discussed.

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Section: Electrospun Carbon Nanofibers As Anode Materials For Lithiummentioning

confidence: 99%

A Review of Electrospun Carbon Fibers as Electrode Materials for Energy Storage

Mao¹,

Hatton²,

Rutledge³

2013

COC

133

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“…14,15 In this contribution we present a first systematic study of the cooperative dynamics of EAN + dipolar aprotic solvent mixtures. Acetonitrile (AN) was chosen as the non-ionic component as this industrially important solvent 16,17 is miscible with EAN over the entire composition range. Additionally, its structure and dynamics are well characterized.…”

Section: Introductionmentioning

confidence: 99%

Do H-bonds explain strong ion aggregation in ethylammonium nitrate + acetonitrile mixtures?

Sonnleitner

Nikitina

Nazet

et al. 2013

Phys. Chem. Chem. Phys.

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Binary mixtures of the protic ionic liquid ethylammonium nitrate (EAN) and acetonitrile (AN) were studied at 25 1C over the entire composition range by means of broadband dielectric spectroscopy covering 0.2 r n/GHz r 89. The dielectric spectra could be decomposed into two relaxation processes, both of which proved to be composite modes. For dilute solutions the higher-frequency Debye relaxation centered at B60 GHz is associated with the rotational diffusion of AN molecules, whereas at higher salt concentrations ultra-fast intermolecular vibrations and librations of EAN dominate the process. For EAN-rich solutions the lower-frequency relaxation is mainly due to jump reorientation of the ethylammonium cation, whereas contact ion pairs (CIPs) dominate this mode for dilute solutions. From the relaxation amplitudes effective solvation numbers and ion-pair concentrations were determined. For vanishing EAN mole fraction, x EAN -0, an effective cation solvation number of B7 was found which steeply drops until x EAN E 0.2 but shows only moderate decrease later on. The obtained association constant for EAN, K 0 A = 970 L mol À1 , exceeds that of other 1 : 1 electrolytes in AN by a factor of B30-50. This observation, as well as the fact that CIPs are formed despite strong cation solvation, indicates that ion pairing is mainly driven by the formation of strong hydrogen bonds between anions and cations.

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“…On the contrary, the electrochemical capacitors have 26 higher power density and longer lifetime exhibiting high coulom- 27 bic efficiency, larger current density and fast start-up response, 28 although they have a lower energy density [1,2]. Based on the 29 above considerations, the supercapacitors can be used to deliver 30 a high power demand during a short time, without damaging the 31 power train system, when hybrid-electric and fuel cell vehicles are 32 accelerated and to recover the energy when they are braked [3,4]. 33 Usually, commercial supercapacitors are made of high-surface 34 area activated carbons in various forms and work in a symmet- 35 ric mode, that is, the same activated carbon is used in the positive 36 and negative electrodes.…”

mentioning

confidence: 99%