Electrochemical capacitors with KCl electrolyte

Lee, Hee Y.; Venkatesan, M.; Goodenough, John B.

doi:10.1016/s1387-1609(00)88567-9

Cited by 87 publications

(93 citation statements)

References 14 publications

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“…This means that the peak B (amorphous LFP) characteristic is associated with a fast, nondiffusionlimited, surface reaction such as observed for pseudocapacitive materials. Differently from MnO 2 [4,5], TiO 2 [6] or Nb 2 O 5 [16], this pseudocapacitive behavior is extrinsic in origin, since it is related to the presence of Fe 3+ defects in the structure [15,21,22]. To get further insights on the electrochemical reaction kinetics in the two different potential ranges (peaks A and B), we divided the total current into two contributions such as proposed by Dunn's group [15,16,26,27].…”

Section: Resultsmentioning

confidence: 99%

“…A promising route to increase the energy density of supercapacitors is designing hybrid supercapacitors where an activated carbon electrode is combined with a fast, faradic charge storage electrode [3]. Pseudocapacitive materials with fast redox reactions confined at the surface of materials have been proposed as the faradic electrode, such as transition metal oxides [4][5][6][7] or two-dimensional transition metal carbides [8,9]. However, most of these pseudocapacitive materials operate in aqueous electrolytes, thus limiting their practical interest for high-energy supercapacitor applications.…”

Section: Introductionmentioning

confidence: 99%

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Electrochemical kinetics of nanostructure LiFePO 4 /graphitic carbon electrodes

Kisu

Iwama

Naoi³

et al. 2016

Electrochemistry Communications

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a b s t r a c tLithium cation insertion/deinsertion reaction kinetics in a LiFePO 4 (LFP)/graphitic carbon composite material were electrochemically studied with a cavity microelectrode (CME). The LFP/graphitic carbon composite has a core LFP (crystalline/amorphous)/graphitic carbon shell structure. In the crystalline and amorphous LFP phase, different reaction mechanisms were observed and characterized. While the reaction mechanism in the crystalline LFP phase is controlled by Li + diffusion, the amorphous LFP phase shows a fast, surface-controlled, pseudocapacitive charge-storage mechanism. This pseudocapacitive behavior is extrinsic in origin since it comes from the presence of Fe 3+ defects in the structure. These features explain the ultrafast performance of the material which offers interesting opportunities as a positive electrode for assembling high power and high energy hybrid supercapacitors.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Electrochemical kinetics of nanostructure LiFePO 4 /graphitic carbon electrodes

Kisu

Iwama

Naoi³

et al. 2016

Electrochemistry Communications

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“…z E-mail: daniel.buchholz@kit.edu; stefano.passerini@kit.edu layered K x MnO 2 · (0.3 ≤ y ≤ 0.6) H 2 O has been reported as cathode material in aqueous K-ion capacitors. 16,17 With respect to non-aqueous electrolytes, A. Eftekhari studied the use of Prussian blue as active material in combination with potassium metal using 1 M KBF 4 in EC:EMC (30:70 wt.) electrolyte in 2004.…”

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confidence: 99%

Non-Aqueous K-Ion Battery Based on Layered K_0.3MnO₂and Hard Carbon/Carbon Black

Vaalma

Giffin

Buchholz

et al. 2016

J. Electrochem. Soc.

372

335

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Herein, we present the synthesis and characterization of negative (a hard carbon/carbon black composite) and positive (K0.3MnO2) active materials for K-ion batteries as well as their combination in a non-aqueous K-ion cell. The hard carbon/carbon black composite can deliver up to 200 mAh g−1 while the layered birnessite K0.3MnO2 delivers up to 136 mAh g−1. The K-ion cell exhibits an interesting and encouraging cycling performance for 100 cycles. These exciting new insights demonstrate the potential of K-ion batteries, which are worth to be further investigated in greater detail.

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“…[3][4][5][6][7][8] Electrolytes near neutral pH are selected for materials that are not as corrosion-resistant in acids and base, for example manganese oxide. [9][10][11][12] Neutral electrolytes are more environmentally benign and its low corrosiveness allows a wider range in choice for periphery material, such as current collectors and packaging. 13 Despite the RuO 2 -based material being the model pseudocapacitive material, studies on the electrochemical capacitor behavior in neutral electrolytes are scarce compared to the more popular acidic or basic electrolytes.…”

mentioning

confidence: 99%

Towards Implantable Bio-Supercapacitors: Pseudocapacitance of Ruthenium Oxide Nanoparticles and Nanosheets in Acids, Buffered Solutions, and Bioelectrolytes

Makino

Ban

Sugimoto

2015

J. Electrochem. Soc.

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Metal oxides, in particular ruthenium-based oxides, are promising electrode materials for aqueous pseudocapacitors. Strong acids or bases are favored over neutral electrolytes owing to the higher capacitance. Here we explore the pseudocapacitive behavior of ruthenium oxide nanoparticles and nanosheets in near neutral pH as an environmentally benign electrolyte. The pseudocapacitive charge storage in poorly-crystalline hydrous RuO 2 nanoparticles, and highly-crystalline RuO 2 nanosheets were investigated in acetic acid-lithium acetate (AcOH-AcOLi) buffered solutions. It is shown that capacitance values as high as 1,038 F g −1 can be achieved in AcOH-AcOLi buffered solutions with RuO 2 nanosheets, which is 44% higher than the benchmark RuO 2 · nH 2 O in H 2 SO 4 electrolyte (720 F g −1 ). Furthermore, comparable performance was obtained in phosphate buffered saline and fetal bovine serum. The mechanism of the pseudocapacitive properties is discussed based on the difference in the surface redox behavior of different RuO 2 nanomaterials in acid, neutral, buffered solutions, and in weak acid. Electrochemical capacitors (also known as supercapacitors) are energy harvesting devices capable of charge and discharging within a few seconds, and cycle life in the order of thousands of cycles. Some metal-oxides are known to provide high capacitance in aqueous electrolytes, owing to the combination of the non-faradaic electrical double layer charging and the faradaic surface or near surface confined redox capacitance (psuedocapacitance).1 Pseudocapacitance is a phenomenon generally observed in aqueous electrolytes.2 Acidic or basic electrolytes such as H 2 SO 4 and KOH are favorable in terms of power density owing to the high conductivity. RuO 2 is one of the rare oxides that is stable in both acidic and basic conditions. Hydrous RuO 2 nanoparticles (RuO 2 · nH 2 O; where n is typically 0.5) offers capacitance of ∼700 F g −1 in H 2 SO 4 electrolyte and can be cycled for thousands of cycles with practically no decay, thus is often used for performance benchmarking of new electrode materials. Although studies on the asymmetric systems and applicability of non-aqueous electrolytes to oxide electrodes in order to widen the operating voltage window have recently been initiated, non-aqueous electrolytes have yet to surpass aqueous electrolytes in terms of specific capacitance. [3][4][5][6][7][8] Electrolytes near neutral pH are selected for materials that are not as corrosion-resistant in acids and base, for example manganese oxide.9-12 Neutral electrolytes are more environmentally benign and its low corrosiveness allows a wider range in choice for periphery material, such as current collectors and packaging.13 Despite the RuO 2 -based material being the model pseudocapacitive material, studies on the electrochemical capacitor behavior in neutral electrolytes are scarce compared to the more popular acidic or basic electrolytes. One of the reasons is that the capacitance of RuO 2 in neutral electrolytes is generally 1/2 of that in s...

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Electrochemical capacitors with KCl electrolyte

Cited by 87 publications

References 14 publications

Electrochemical kinetics of nanostructure LiFePO 4 /graphitic carbon electrodes

Electrochemical kinetics of nanostructure LiFePO 4 /graphitic carbon electrodes

Non-Aqueous K-Ion Battery Based on Layered K_0.3MnO₂and Hard Carbon/Carbon Black

Towards Implantable Bio-Supercapacitors: Pseudocapacitance of Ruthenium Oxide Nanoparticles and Nanosheets in Acids, Buffered Solutions, and Bioelectrolytes

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Electrochemical capacitors with KCl electrolyte

Cited by 87 publications

References 14 publications

Electrochemical kinetics of nanostructure LiFePO 4 /graphitic carbon electrodes

Electrochemical kinetics of nanostructure LiFePO 4 /graphitic carbon electrodes

Non-Aqueous K-Ion Battery Based on Layered K0.3MnO2and Hard Carbon/Carbon Black

Towards Implantable Bio-Supercapacitors: Pseudocapacitance of Ruthenium Oxide Nanoparticles and Nanosheets in Acids, Buffered Solutions, and Bioelectrolytes

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Non-Aqueous K-Ion Battery Based on Layered K_0.3MnO₂and Hard Carbon/Carbon Black