Novel insight into neutral medium as electrolyte for high-voltage supercapacitors

Fic, Krzysztof; Lota, Grzegorz; Meller, Mikołaj; Frąckowiak, Elżbieta

doi:10.1039/c1ee02262h

Cited by 740 publications

(479 citation statements)

References 36 publications

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“…It has been reported that symmetric supercapacitors with wide voltage range, higher than the theoretical limit of water, can be overcome with pH-neutral electrolytic solutions of inorganic salts such as Li 2 SO 4 , Na 2 SO 4 and K 2 SO 4 with the Li 2 SO 4 being the most promising salt to date. 72 As explained by Fic et al, 72 the Li + and SO 4 2− ions are strongly solvated in the water molecules. The energy needed to decompose the water competes with the solvating energy.…”

Section: Resultsmentioning

confidence: 92%

High-Voltage Symmetric Supercapacitor Based on 2D Titanium Carbide (MXene, Ti₂CT_x)/Carbon Nanosphere Composites in a Neutral Aqueous Electrolyte

Melchior

Raju

Ike

et al. 2018

J. Electrochem. Soc.

119

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The energy storage performance of one of the lightest-known MXenes, Ti 2 CT x (MX) combined with carbon nanospheres (CNS) has been investigated as a symmetric electrode system in an aqueous electrolyte (1 M Li 2 SO 4 ). The energy storage properties were interrogated using cyclic voltammetry (CV), galvanostatic cycling with potential limitation (GCPL), electrochemical impedance spectroscopy (EIS) and voltage-holding tests. The combined material (MX/CNS) demonstrated a higher specific capacity compared to each of the individual components. The material was fabricated with relatively high and low mass loadings, assembled into a symmetric device and performance compared. Specific capacitance, specific power and specific energy for the lower electrode mass loading of 180 F·g −1 , 37.6 kW·kg −1 and 14.1 W·h·kg −1 were all higher than 86 F·g −1 , 20.1 kW·kg −1 and 6.7 W·h·kg −1 for the higher mass loading. A wide voltage window of 1.5 V was obtained, but with limited long-term cycling behavior, suggesting the need for future improvement. Mathematical modelling and simulation of the supercapacitor showed good correlation with the experimental results, validating the model. The results reveal the potential of the Ti 2 CT x to be employed as a viable energy storage system for lightweight applications. As part of the increasing role of clean energy technologies, electrochemical capacitors (ECs) are continuously evolving components that contribute to meeting the demands of electronic apparatuses and systems and are projected to be even more significant in the future.1 In 2011, Gogotsi and co-workers, 2 first synthesized a two-dimensional (2-D) layered material called MXene, by selectively etching aluminum (Al), using hydrofluoric acid (HF) from the MAX phase material. MAX phase materials are layered ternary carbide and nitride materials with the general chemical formula of M n+1 AX n (where 'M' represents an early transition metal, 'A' represents a group IIIA or IVA element, 'X' is C and/or N, and n may equal 1, 2, or 3). There are more than 70 different MAX phase compositions currently known. 3,4 MXenes are formed when the 'A' element is etched out of the MAX phase material, and subsequently have a general formula of M n+1 X n T x (where T represent surface functional groups such as F, OH or O, and x is the number of functional groups that are attached to the surface following the etching process).5 This newly discovered family of materials has similar properties to graphene with good electronic conductivity and different surface terminations enabling the possibility to manipulate their properties to fit different applications. 2-D materials potentially have large electroactive surfaces and therefore attract research attention. MXenes are currently studied, both theoretically and experimentally, as potential electrode materials for energy storage devices such as batteries [6][7][8][9][10][11][12][13][14][15][16] and ECs 9,14,17-32 as well as other uses. 33,34Although the MXene materials do not possess such a high surface ...

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Section: Resultsmentioning

confidence: 92%

High-Voltage Symmetric Supercapacitor Based on 2D Titanium Carbide (MXene, Ti₂CT_x)/Carbon Nanosphere Composites in a Neutral Aqueous Electrolyte

Melchior

Raju

Ike

et al. 2018

J. Electrochem. Soc.

119

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“…~2 V). Recently Fic et al [5] designed an activated carbon (AC) symmetric supercapacitor exhibiting a specific capacitance of 120 F.g -1 after 15 000 cycles in a working potential of 2.2 V in 1M Li 2 SO 4 aqueous electrolyte. Furthermore, novel asymmetric supercapacitors based on carbon in 1M H 2 SO 4 have demonstrated high stability after 10,000 cycles at 1.6 V [6].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of 3D porous carbon based on cheap polymers and graphene foam for high-performance electrochemical capacitors

Barzegar

Bello

Fashedemi

et al. 2015

Electrochimica Acta

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A scalable production of high surface area nanoporous carbon material (~ 2994 m 2 g -1 ) with good distribution of micro-, meso-and macro-pores was hydrothermally synthesized using both cheap polymers and graphene foam as carbon sources. The as synthesised material shows a unique interconnected porous graphitic structure. The electrochemical double-layer capacitor fabricated from this nanoporous carbon material exhibited a superior supercapacitive performance of 188 F g -1 at current density 0.5 A g -1 . This corresponded to areal capacitance of 6.3 µF cm -2 coupled with a high energy of 0.56 µWh cm -2 (16.71 Wh kg -1 ) and a power density of 13.39 µW cm -2 (401 W kg -1 ) due to extended potential window of 1.6 V in KOH aqueous electrolyte. Moreover, no capacitance loss after 10,000 cycles was observed, owing to the 2 unique structure and large surface area of the active material. The outstanding performance of this material as supercapacitor electrode shows that it has great potential for high performance energy-related applications.

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“…We are also aware that most reported high-potential aqueous ECs used pH-neutral electrolytes. 16,34 To understand this phenomenon, we measure the potential of zero charge (PZC) for the carbon film electrodes in acidic or alkaline electrolytes before cycling. At pH 10, the measured PZC is −0.051 V vs Ag/AgCl (0.15 V vs SHE), while at pH 1, the PZC is 0.39 V vs Ag/AgCl (0.59 V vs SHE).…”

Section: Resultsmentioning

confidence: 99%

“…The electrolyte salts mater as well, where due to the strong solvation effect of Li + and SO 4 2− ions, ECs using a Li 2 SO 4 electrolyte can be cycled to 2.2 V in CV tests. 34 Very recently, Suo et al reported a "water-in-salt" aqueous electrolyte with 21 m LiTFSI in lithium-ion batteries, which can be polarized to 3.0 V. The high voltage is attributed to the reduced water activity due to the water coordination around Li + and the passivation effect from the reduced TFSI − ions. 35 Hydrogen electrosorption on nanoporous carbon electrodes is another approach to increase the effective charge storage.…”

Section: Vmentioning

confidence: 99%

A 1.8 V Aqueous Supercapacitor with a Bipolar Assembly of Ion-Exchange Membranes as the Separator

Wang

Chandrabose

Jian

et al. 2016

J. Electrochem. Soc.

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We introduce a novel bipolar assembly of ion-exchange membranes as the separator for aqueous supercapacitors. The new bipolar separator enables the positive electrode and the negative electrode to operate in acidic electrolyte and alkaline electrolyte, separately. The bipolar separator increases the theoretically stable voltage window from 1.23 to 1.76 V for the device when pH 1 and pH 10 are selected for the positive and negative electrode, respectively, based on the pH tolerance of commercial ion exchange membranes. By considering the results from comprehensive electrolyte stability investigation, we charge the cells to 1.8 V, which increases the maximum cell discharge voltage to 1.77 V. A specific energy of 12.7 Wh/kg is achieved based on the electrodes' mass, which is twice the value of the comparative best performing single electrolyte. The new cell configuration with the three-compartment bipolar separator effectively prevents the acid/base electrolyte cross diffusion, where after 10,000 cycles, the capacitance retention is 97% with coulombic efficiency maintained above 99.6% all through cycling. Supercapacitors, also known as ultracapacitors or electrochemical capacitors (ECs), are highly complementary to batteries by providing high power density and ultra-long cycling life that the state-of-theart batteries have yet to achieve.1 These devices are indispensable in applications, including power cranking for transportation, energy recovery in heavy-duty systems 2 and potentially laser generation. In order to develop more powerful ECs, prior works have studied the impacts of carbon electrodes' properties on ECs' performance, including surface area, 3-8 pore size, 9-14 heteroatom doping, 15-19 and pseudocapacitance. [20][21][22][23][24][25][26][27] Recently, attention has also been paid to redox-active electrolytes. [28][29][30][31][32]47 As well known, most commercial ECs employ non-aqueous electrolyte rather than aqueous electrolyte despite the facts that aqueous electrolytes are typically more conductive, safer and cheaper. The overwhelming advantage of non-aqueous electrolyte is its much wider stable electrochemical potential window than its aqueous counterpart, where the latter is limited to 1.23 V, the potential gap between the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER).1 Therefore, the operating voltage for aqueous ECs is normally below 1.2 V, whereas it is as high as 3.0 V for non-aqueous devices. The energy density of capacitors obeys the following equation: E = 1 8 C V2 , where C is the specific capacitance of one electrode and V is the maximum discharge voltage of a device. Although the electrode capacitance in aqueous ECs is often higher than that in nonaqueous ECs, the overall energy density of the former still falls far below what the latter could offer.In order to cultivate the advantages of aqueous supercapacitors, it is highly desirable to increase its operating voltage without decomposing its electrolyte. One example is lead-acid batteries that operate at a voltage...

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Novel insight into neutral medium as electrolyte for high-voltage supercapacitors

Cited by 740 publications

References 36 publications

High-Voltage Symmetric Supercapacitor Based on 2D Titanium Carbide (MXene, Ti₂CT_x)/Carbon Nanosphere Composites in a Neutral Aqueous Electrolyte

High-Voltage Symmetric Supercapacitor Based on 2D Titanium Carbide (MXene, Ti₂CT_x)/Carbon Nanosphere Composites in a Neutral Aqueous Electrolyte

Synthesis of 3D porous carbon based on cheap polymers and graphene foam for high-performance electrochemical capacitors

A 1.8 V Aqueous Supercapacitor with a Bipolar Assembly of Ion-Exchange Membranes as the Separator

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Novel insight into neutral medium as electrolyte for high-voltage supercapacitors

Cited by 740 publications

References 36 publications

High-Voltage Symmetric Supercapacitor Based on 2D Titanium Carbide (MXene, Ti2CTx)/Carbon Nanosphere Composites in a Neutral Aqueous Electrolyte

High-Voltage Symmetric Supercapacitor Based on 2D Titanium Carbide (MXene, Ti2CTx)/Carbon Nanosphere Composites in a Neutral Aqueous Electrolyte

Synthesis of 3D porous carbon based on cheap polymers and graphene foam for high-performance electrochemical capacitors

A 1.8 V Aqueous Supercapacitor with a Bipolar Assembly of Ion-Exchange Membranes as the Separator

Contact Info

Product

Resources

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High-Voltage Symmetric Supercapacitor Based on 2D Titanium Carbide (MXene, Ti₂CT_x)/Carbon Nanosphere Composites in a Neutral Aqueous Electrolyte

High-Voltage Symmetric Supercapacitor Based on 2D Titanium Carbide (MXene, Ti₂CT_x)/Carbon Nanosphere Composites in a Neutral Aqueous Electrolyte