A self-branched lamination of hierarchical patronite nanoarchitectures on carbon fiber cloth as novel electrode for ionic liquid electrolyte-based high energy density supercapacitors

This is the peer reviewed version of the following article: Ramu, M., Chellan, J. R., Goli, N., Joaquim, P., Cristobal, V., Kim, B. C., A Self‐Branched Lamination of Hierarchical Patronite Nanoarchitectures on Carbon Fiber Cloth as Novel Electrode for Ionic Liquid Electrolyte‐Based High Energy Density Supercapacitors. Adv. Funct. Mater. 2019, 1906586. https://doi.org/10.1002/adfm.201906586, which has been published in final form at https://doi.org/10.1002/adfm.201906586. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.The developments of rationally designed binder-free metal chalcogenides decorated flexible electrodes are of paramount importance for advanced energy storage devices. Herein, binder-free patronite (VS4) flower-like nanostructures are facilely fabricated on a carbon cloth (CC) using a facile hydrothermal method for high-performance supercapacitors. The growth density and morphology of VS4 nanostructures on CC are also controlled by varying the concentrations of vanadium and sulfur sources along with the complexing agent in the growth solution. The optimal electrode with an appropriate growth concentration (VS4-CC@VS-3) demonstrates a considerable pseudocapacitance performance in the ionic liquid (IL) electrolyte (1-ethyl-3-methylimidazolium trifluoromethanesulfonate), with a high operating potential of 2 V. Utilizing VS4-CC@VS-3 as both positive and negative electrodes, the IL-based symmetric supercapacitor is assembled, which demonstrates a high areal capacitance of 536 mF cm-2 (206 F g-1) and excellent cycling durability (93%) with superior energy and power densities of 74.4 µWh cm-2 (28.6 Wh kg-1) and 10154 µW cm-2 (9340 W kg-1), respectively. As for the high energy storage performance, the device stably energizes various portable electronic applications for a long time, which make the fabricated composite material open up news for the fabrication of fabrics supported binder-free chalcogenides for high-performance energy storage devices.Peer ReviewedPostprint (author's final draft

Expeditious and eco-friendly hydrothermal polymerization of PEDOT nanoparticles for binderfree high performance supercapacitor electrodes

Poly(3,4-ethylenedioxythiophene) (PEDOT) is a promising conjugated polymer that has attracted attention because of its outstanding electronic properties, useful for a wide range of applications in energy storage devices. However, synthesis of high-quality PEDOT occurs via vapour phase polymerization and chemical vapour deposition techniques using extrinsic hard templates or complicated experimental setups. This study introduces a simple hydrothermal polymerization technique using ferric chloride (FeCl3) as an oxidizing agent to overcome the above drawback, which results in good conductive, crystalline PEDOT nanodendrites and nanospheres. The effects of varying the molar ratio of FeCl3 oxidant were investigated in terms of the structural, morphological and electrochemical properties of PEDOT. The supercapacitive performance of the as-polymerized PEDOT nanostructures was determined by fabricating an electrode without the aid of organic binders or conductive additives. PEDOT nanodendrites polymerized using 2.5 molar ratio of FeCl3 demonstrated enhanced electrochemical performance with a maximum specific capacitance of 284 F g-1 with high energy density of 39.44 W h kg-1 at 1 A g-1 current density in 1 M H2SO4 electrolyte. Moreover, the sample possessed higher conductivity, better specific surface area, improved electrochemical properties, comparable crystallinity, and excellent cycling stability after 5000 charge/discharge cycles than the other PEDOT nanostructures. Importantly, the results establish that these materials afford good redox behaviors with better conductivity suitable for the development of an organic electrode-based supercapacitor with high specific charge capacity and stability

Protonated nickel 2-methylimidazole framework as an advanced electrode material for high-performance hybrid supercapacitor

© 2021 Elsevier. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/Metal-organic frameworks (MOFs) with high conductivity have proven to be an exciting electrode material for energy storage devices. However, most of the MOFs exhibit a low electrical conductivity, which limits their use in supercapacitors. To overcome this issue herein, a simple acid treatment method was adopted to obtain nanoflower-like nickel 2-methylimidazole framework (Ni-MOF) to improve the electrical conductivity without disrupting its framework. The sample treated with a solution of sulfuric acid (H2SO4) at optimal pH 2 (Ni-MOF-2), exhibited improved surface texture with excellent electrochemical characteristics. The Ni-MOF-2 sample displayed a high specific capacity (Cs) of 467 C/g at 1 A/g in aqueous 6 M potassium hydroxide (KOH) electrolyte than that of other samples. This is mainly due to enhanced proton conduction in Ni-MOF-2 after acid treatment. In addition, a hybrid supercapacitor (HSC) device was fabricated using battery-type Ni-MOF-2 as a positive electrode and heteroatomenriched activated carbon (O, N, S@AC) as a negative electrode. The fabricated HSC exhibited a maximum specific capacity (Cs) of 38 mAh/g with high specific energy (Es) 39 Wh/kg and maximum specific power (Ps) of 11,079 W/kg. Moreover, the HSC displayed excellent cyclic stability of ~87% for 10,000 continuous galvanostatic charge/discharge (GCD) cycles.Peer ReviewedPostprint (author's final draft

Electrochemical polymerization of chloride doped PEDOT hierarchical porous nanostructure on graphite as a potential electrode for high performance supercapacitor

International audienc

A high performance PEDOT/PEDOT symmetric supercapacitor by facile in-situ hydrothermal polymerization of PEDOT nanostructures on flexible carbon fibre cloth electrodes

Achievement of conducting polymer based symmetric supercapacitor with high specific capacitance and long cyclic stability is a very challenging and a complicated approach. Generally, the specific capacitance and stability of the conducting polymer system have been improved by forming composite with metal oxides or carbon based nanomaterials. In this present work, we demonstrated a simple and straightforward strategy for the deposition of bare PEDOT nanostructures on flexible 3D carbon fibre cloth (CFC) via in situ hydrothermal polymerization technique. The hydrot hermally polymerized electrodes were easily assembled into PEDOT/PEDOT symmetrical supercapacitor without using any organic binders and conductive additives. This symmetric supercapacitor exhibited significantly high specific capacitance of 203 F g −1 at 5 mV s −1 scan rate with high energy density of 4.4 W h kg −1 and power density of 40.25 kW kg −1 in 1 M H 2 SO 4 electrolyte, which is highest value reported for this material as a symmetric device. More importantly, the formation of 3D PEDOT nanostructure with flexible carbon cloth affords an efficient and stable electrode for facile electron transfer in symmetrical supercapacitor and delivered a long device stability with capacitance retention of ∼86% after 12,000 charge/discharge cycles

Direct fabrication of two-dimensional copper sulfide nanoplates on transparent conducting glass for planar supercapacitor

An in-planar two-dimensional supercapacitor was fabricated utilizing chemically deposited copper sulfide (CuS) nanoplates on patterned fluorine doped tin oxide (FTO) glass substrate. The morphology and structural properties of the CuS thin films were analyzed using scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The fabricated CuS planar supercapacitor device demonstrated a promising electrochemical performance due to the pseudocapacitance induced by Li + ions intercalation/deintercalation process on the electrode surface. A maximum areal capacitance of 4.9 mF cm −2 was delivered by the CuS thin film device with an energy and power density of 4 x 10 −7 W h cm −2 and 2 mW cm −2 respectively. Moreover, the planar supercapacitor exhibited an excellent cyclic stability of ∼94% capacitance retention after 5000 charge/discharge cycles

A self-branched lamination of hierarchical patronite nanoarchitectures on carbon fiber cloth as novel electrode for ionic liquid electrolyte-based high energy density supercapacitors

This is the peer reviewed version of the following article: Ramu, M., Chellan, J. R., Goli, N., Joaquim, P., Cristobal, V., Kim, B. C., A Self‐Branched Lamination of Hierarchical Patronite Nanoarchitectures on Carbon Fiber Cloth as Novel Electrode for Ionic Liquid Electrolyte‐Based High Energy Density Supercapacitors. Adv. Funct. Mater. 2019, 1906586. https://doi.org/10.1002/adfm.201906586, which has been published in final form at https://doi.org/10.1002/adfm.201906586. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.The developments of rationally designed binder-free metal chalcogenides decorated flexible electrodes are of paramount importance for advanced energy storage devices. Herein, binder-free patronite (VS4) flower-like nanostructures are facilely fabricated on a carbon cloth (CC) using a facile hydrothermal method for high-performance supercapacitors. The growth density and morphology of VS4 nanostructures on CC are also controlled by varying the concentrations of vanadium and sulfur sources along with the complexing agent in the growth solution. The optimal electrode with an appropriate growth concentration (VS4-CC@VS-3) demonstrates a considerable pseudocapacitance performance in the ionic liquid (IL) electrolyte (1-ethyl-3-methylimidazolium trifluoromethanesulfonate), with a high operating potential of 2 V. Utilizing VS4-CC@VS-3 as both positive and negative electrodes, the IL-based symmetric supercapacitor is assembled, which demonstrates a high areal capacitance of 536 mF cm-2 (206 F g-1) and excellent cycling durability (93%) with superior energy and power densities of 74.4 µWh cm-2 (28.6 Wh kg-1) and 10154 µW cm-2 (9340 W kg-1), respectively. As for the high energy storage performance, the device stably energizes various portable electronic applications for a long time, which make the fabricated composite material open up news for the fabrication of fabrics supported binder-free chalcogenides for high-performance energy storage devices.Peer Reviewe

Electrodeposition of vanadium pentoxide on carbon fiber cloth as a binder-free electrode for high-performance asymmetric supercapacitor

Electrodeposition technique is a convenient and robust approach for the development of transition metal oxides as electrodes, particularly for supercapacitor applications. However, achieving uniform coating is difficult and relies on the constrained deposition parameters. Herein, we fabricated the binder-free spiral rope-like structured V2O5 on carbon fiber cloth (CFC) by simple and versatile electrodeposition method for high performance asymmetric supercapacitors. The deposition rate of V2O5 nanostructures on CFC was controlled by varying the electrodeposition duration. The resultant optimum duration (30 min) of the binder-free V2O5@CFC-30 electrode showed an excellent performance with a high areal capacitance of 354 mF/cm2 in 1 M Na2SO4 aqueous electrolyte. Furthermore, the asymmetric supercapacitor (ASC) was developed using V2O5@CFC-30 as a positive electrode and O, N, S enriched activated carbon (O, N, S@AC) as a negative electrode. The ASC demonstrated a maximum device-specific capacitance of 57 F/g, excellent cyclic stability (~94%) even after 10,000 cycles and maximum specific energy (17.7 Wh/kg) and power (2728 W/kg). Furthermore, the flexible supercapacitor delivered maximum specific energy (13 Wh/kg) and power (3871 W/kg) with an outstanding capacity retention of 91% over 4000 cycles. This research makes the electrodeposition of V2O5 ideally suited for a binder-free, high performance supercapacitor applications

Electrochemical impedance spectroscopic studies on aging-dependent electrochemical degradation of p-toluene sulfonic acid-doped polypyrrole thin film

The conducting polymer polypyrrole thin film was galvanostatically polymerized on stainless steel substrate for the supercapacitor electrode. The electrochemical stability of the electrode was monitored each 30 days of aging up to 90 days. The FTIR analysis showed an increase in intensity of the absorption peaks, especially high growth of the carbonyl peaks after 90 days of aging. The electrochemical capacitance degradation of the electrode was studied using cyclic voltammetric and galvanostatic charge/discharge analysis in 1 M Na 2 SO 4 electrolyte, which showed ~ 53% of fading in the initial specific capacitance value after 90 days. Further, the electrochemical degradation of polypyrrole electrodes was analyzed in detail using electrochemical impedance spectroscopy. The analysis showed a large increase in the internal resistance and low-power deliverability of the electrode with respect to aging as the main reasons for the degradation of specific capacitance of the polypyrrole electrode