Search

Graphical abstract Highlights • Ag nanoparticles decorated La 0.85 Sr 0.15 MnO 3 electrode was designed firstly. • The addition of Ag can contribute a small amount of pseudocapacitance. • The as-prepared composite electrode shows superior electrochemical behavior. • It has excellent cycling life with ∼100% capacitance retention after 1000 cycles. • It has energy density of 20.6 Wh·kg−1 and high power density of 8500 W·kg−1. Abstract Ag nanoparticles decorated La 0.85 Sr 0.15 MnO 3 was designed and used as electrode for supercapacitors firstly. Ag nanoparticles not only facilitate to accelerate charge transfer but also contribute a small amount of pseudocapacitance. It shows a high specific capacitance of 186 F·g−1 at 1 A·g−1 and excellent cycling performance. When assembled asymmetric supercapacitor, it possesses maximum energy density of 20.6 Wh·kg−1 at power density of 1700 W·kg−1 within the wide potential window of 1.7 V, as well as 13.4 Wh·kg−1 at 8500 W·kg−1. This work could prompt the development and application of high conductivity nanoparticles modified perovskite in supercapacitors. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A novel MnO 2 /g-C 3 N 4 @PPy ternary nanocomposite was designed and fabricated. • The ternary nanocomposite exhibited highly enhanced supercapacitor performance. • The ternary nanocomposite possessed outstanding cyclic stability. Abstract In this work, a novel MnO 2 /g-C 3 N 4 @polypyrrole (PPy) ternary nanocomposite (NC) was fabricated by coupling the MnO 2 nanorods with the two-dimensional g-C 3 N 4 sheets and the conductive PPy. The MnO 2 /g-C 3 N 4 @PPy NC electrode exhibited a high specific capacitance of 274 F g−1 at a current density of 2 A g−1, which was 1.88 times than that of the MnO 2 @PPy NC electrode. The MnO 2 /g-C 3 N 4 @PPy NC electrode also possessed outstanding cyclic stability with 95% capacitance retention after 1000 cycles. The present strategy for fabricating ternary nanocomposite uses low-cost raw materials and simple preparation method, which provides an alternative route to optimize the SC performance of other pseudocapacitive oxides. [ABSTRACT FROM AUTHOR]

Highlights • Ultrathin carbon nanosheet-supported Ni quantum dot hybrids were fabricated. • Starch is used as the source of ultrathin carbon nanosheet. • The hybrids exhibited high specific capacitance and excellent rate capability. • The hybrids exhibited outstanding cycling stability. Abstract Ultrathin carbon nanosheet-supported Ni quantum dot hybrids (C-Ni-QDs) were synthesized via a two-step process. The obtained hybrid materials exhibited high specific capacitance of 1120 F g−1 at 2 A g−1 and excellent rate capability with a retention ratio of 81.3% at 20 A g−1. Besides, the C-Ni-QDs hybrids also exhibited outstanding cycling stability with a capacitance retention of 97.0% after 2000 cycles. These results indicated that C-Ni-QDs hybrids could be a promising material for supercapacitors. [ABSTRACT FROM AUTHOR]

Highlights • Carbon-coated copper sulfide nanocomposite prepared via two-step sulfidation. • Cu 7 S 4 /C nanocomposite is ∼100 nm in size. • Cu 7 S 4 /C electrode exhibits highest capacitance (321.9 F g−1) at 0.5 A g−1. Abstract Metal-organic framework (MOF)-derived carbon-coated metal sulfides are a popular research area for energy storage, owing to their highly reactive nature and universal electrochemical activity. A simple and efficient method for the preparation of carbon-coated copper sulfide via a calcining-hydrothermal process using an MOF template is presented in this paper. The transmission electron microscope (TEM) imaging indicates that the cobble-like Cu 7 S 4 nanopolyhedra are ∼100 nm in size, and are interconnected by amorphous carbon. Electrochemical analysis shows that the Cu 7 S 4 /C electrode possesses the highest capacitance, 321.9 F g−1 (80.5 mAh g−1 in capacity), at a current density of 0.5 A g−1, and achieves nearly 78.1% capacitance retention after 3000 cycles, suggesting its holds promise for application in battery-type electrode materials for supercapacitors. [ABSTRACT FROM AUTHOR]

We have synthesized book-like Co 3 O 4 microstructures on copper form by hydrothermal and annealing process, which can be directly used as binder-free, excellent rate capability and long-life supercapacitor electrode. The random slant book-like Co 3 O 4 microstructures were uniformly grown on the Cu substrate, and the electrode exhibited a high specific capacitance of 736.25 F g −1 at a current density of 1 A g −1 , good coulombic efficiency of 82.6%, excellent rate capability and 78.13% capacity retaining after 5000 cycles of charge and discharge, demonstrating a great potential in high power storage devices application. [ABSTRACT FROM AUTHOR]

Sphere-feature MoSe 2 has been synthesized by using a facile hydrothermal method. The electrochemical properties of the as-prepared materials have been investigated for supercapacitors. Electrochemical measurements show that MoSe 2 spheres exhibit a specific capacitance of 243 F/g at 0.5 A/g, and still kept 90.3% capacitance after 1000 cycles at 1 A/g, indicating MoSe 2 sphere could be a promising candidate for high-performance supercapacitor applications. [ABSTRACT FROM AUTHOR]

Vertically assembled two-dimentional materials have great scientific and technological promise. In this work, altrathin atom doped graphitic carbon nitride (g-C 3 N 4 ) was synthesised via thermal treatment of thiourea and KBr/NaBr. Free-standing manganese dioxide nanoflakes were uniformly grown on K/Na doped g-C 3 N 4 through hydrothermal reaction. The K doped g-C 3 N 4 @ MnO 2 has a specific capacitance twice higher than that of pure g-C 3 N 4 @ MnO 2 . This unique design brought excellent specific capacitance (375 F g −1 ) and cycle stability, which showed that atom doping is an effective approach to enhance electrochemical performance. In addition, the low cost, facial synthesis and small amount of addings make this strategy an optimized approach to construct g-C 3 N 4 based electrode materials. [ABSTRACT FROM AUTHOR]

• The NiCoS@NiMo-LDH hierarchical composites are synthesized on Ni foam. • NiCoS@NiMo-LDH nanostructure provides abundant active sites and enough ion channels. • The binder-free NiCoS@NiMo-LDH electrode exhibits excellent electrochemical properties. • The fabricated ASC device exhibits a high energy density and good stability. Ni(OH) 2 ·0.75H 2 O nanosheets embedded with NiMoO 4 nanoparticles (NiMo-LDH) supported by nickel cobalt sulfur (NiCoS) nanorods were prepared by a multi-step hydrothermal method, which provides an effective channel for ion transport and abundant active sites for charge storage. The NiCoS@NiMo-LDH electrode exhibited a very high capacitance of 1302.5 μAh cm−2 at 10 mA cm−2, with 54 % capacitance retention observed at 50 mA cm−2. The asymmetric supercapacitor (ASC) assembled with the NiCoS@NiMo-LDH as the positive electrode and active carbon (AC) as the negative electrodes which exhibits an energy density of 1096.6 μWh cm−2 at a power density of 2.8 mW cm−2 along with good stability of 86.67 % after 5000 cycles. [ABSTRACT FROM AUTHOR]

Simple hydrothermal method was adopted to synthesize zero dimensional 14-facets (6 squares and 8 cuboids) NiCo 2 S 4 cubohexa-octahedral (NCS-COH) shaped nanostructures for high performance supercapacitor properties. The as-prepared nanostructures were characterized using X-ray powder diffraction, scanning and transmission electron microscopy. A plausible formation mechanism was also proposed along with crystal structure of NCS-COH. The exceptional architectures fashioned an ultrafast electron transfer during electrochemical reaction. The NCS-COH electrode exhibited a high specific capacitance of 835 at 1 A/g and capacitance retention of 92.7% at 10 A/g after 5000 cycles. [ABSTRACT FROM AUTHOR]

• Pani can be polymerized on PC surface through host–guest interactions. • Ordered polymerization of Pani on PC is achieved by cyclodextrin polymer. • The products exhibit good specific surface area and high specific capacitance. Ordered polymerization of polyaniline (PANI) on porous carbon (PC) was achieved using cyclodextrin polymer (CDP)-functionalization (CDP/PC) on PC. PANI can be polymerized on PC surface through host–guest interactions between aniline monomers and the CDP to form the CDP-PANI/PC composite. CD modification induced the ordered polymerization of aniline monomers. So CDP-PANI/PC exhibited remarkable specific capacitance (739.2 F·g−1 at 1 A·g−1) and high rate capability (516 F·g−1 at 10 A·g−1, retaining 69.8% of its original capacitance) in a three-electrode system. A symmetrical supercapacitor device assembled from CDP-PANI/PC electrodes retained over 81 % of its initial capacitance after 5000 cycles at 5 A·g−1. [ABSTRACT FROM AUTHOR]

A new and facile one-step method to synthesise graphene oxide/natural rubber latex (GO/NRL) nanocomposite was achieved using an electrochemical exfoliation method. In this method, the fabrication of GO/NRL nanocomposite occurs concurrently with GO production that is intermixed with NRL. This approach is a simple and innovative method that succeeded in producing nanocomposite with better conductivity. The samples were characterized using FESEM, HRTEM, FT-IR, UV–vis, micro-Raman spectroscopy, XRD, TGA, I–V and C – V measurements. The C – V analysis showed that the specific capacitance of the samples prepared via the one-step method was 103.7 F g −1 , much better than those produced via a two-step method (32.6 F g −1 ). These results were also consistent with the I–V analysis, in which a higher conductivity value was measured for the one-step method (7.12×10 −5 S cm −1 ) than for the two-step method (3.62×10 −7 S cm −1 ). In conclusion, the one-step method introduced for the fabrication of GO/NRL nanocomposite is a promising method for implementation in supercapacitor applications. [ABSTRACT FROM AUTHOR]

Potentiostatic depositions of zinc oxide (ZnO) on titania (TiO 2 ) nanotube substrate have been observed to demonstrate remarkable enhancement in the supercapacitance behavior as reported in this study. Systematic evaluation of the morphology and crystal structure of the electrodeposited ZnO phase was carried out using scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques, respectively. The cyclic voltammetry and galvanostatic charge–discharge experiments indicated that the electrode can attain a maximum specific capacitance of 304 F g −1 that was partly attributed to the electro-active ZnO phase and partly to the highly permeable, porous, and unidirectional nanotubular TiO 2 substrate. [ABSTRACT FROM AUTHOR]

Layered MoSe 2 nanosheets were prepared on Ni-foam substrate with binder-free via a simple hydrothermal method. As the supercapacitor electrode material, the as-prepared materials showed high specific capacitance (1114.3 F g −1 ) and an extended long cycle life (maintain at least 104.7% after 1500 cycles) due to their specific structure, which showed significant potential for energy storage applications. [ABSTRACT FROM AUTHOR]

• Solvothermal synthesis was used to make MnO 2 /MWCNT nanocomposites. • MnO 2 /MWCNT nanocomposites were employed as a binder-free super capacitor electrode. • MnO 2 /MWCNT electrode has a high specific capacitance and a good rate capability. • MnO 2 /MWCNT electrode annealed at 500 °C has a high specific capacitance of 314F/g. • CV curves of the MnO 2 /MWCNT electrode retain rectangular shape at high scan rates. This study presents the findings of MnO 2 tailoring in MWCNT for supercapacitor applications. Using a solvothermal method, we developed the MnO 2 /MWCNT nanocomposites with high energy storage capacity. The XRD peaks revealed the hexagonal structure of graphite and the tetragonal structure of birnessite type MnO 2. TEM revealed that the MWCNT sidewalls were decorated with a huge number of high purity manganese nanoparticles. According to CV studies, the composite electrode's specific capacitance exceeds 314F/g. As per the researchers, the tailored MnO 2 /MWCNT nanocomposites should promote the best electrode material for supercapacitor applications. [ABSTRACT FROM AUTHOR]

A binder-free composite electrode comprised of nano-WO 3 ·H 2 O/MnO 2 (NWMO) has been synthesized through an anodic deposition technique for supercapacitor application. The composite electrode consists of numerous NWMO nanosheets and shows a porous morphology. Electrochemical tests reveal that the as-prepared NWMO has a high specific capacitance (363 F g −1 at 0.5 A g −1 ) and good rate capability (210.3 F g −1 at 10 A g −1 ), which can be attributed to its unique structure. The capacitance retention still remains 93.8% after 5000 cycles at a relatively high current density of 2 A g −1 . These results indicate that NWMO may have great potential as supercapacitor electrode material. [ABSTRACT FROM AUTHOR]

Abstract: In this work, we developed a one-pot approach to fabricate CoFe2O4/FeOOH nanocomposites without any surfactant. By tailoring the urea concentration, flower-like nanostructures of CoFe2O4/FeOOH nanocomposites can be obtained. The electrochemical properties of the CoFe2O4/FeOOH electrodes were elucidated by cyclic voltammograms, galvanostatic charge/discharge tests and electrochemical impedance spectroscopy in 6M KOH electrolyte. Flower-like CoFe2O4/FeOOH exhibited a specific capacitance of 332.4Fg−1 at the current density of 0.5Ag−1, and excellent cycling stability (91.3% retention after 1000 cycles, 5Ag−1). These findings suggested that this facile synthetic strategy could be useful to design and synthesize hierarchical electrode nanocomposites with enhanced supercapacitive performance. [Copyright &y& Elsevier]

Abstract: A method of electrodeposition under supergravity field is proposed to prepare Ni(OH)2/Ni/graphene composites. Particles composed of Ni(OH)2 and Ni are covered by a thin graphene coating. The Ni(OH)2/Ni/graphene composite is evaluated as electrodes for supercapacitors, which shows that the specific capacitance of Ni(OH)2/Ni/graphene is 2609Fg−1 at a current density of 0.5Ag−1 in 6M KOH solution. In addition, it could still reach 1020Fg−1 at a current density of 4Ag−1. On the other hand, electrodeposition under supergravity field could decrease concentration polarization and promote ion diffusion, which is a promising strategy for the fabrication of nanocomposites. [Copyright &y& Elsevier]

Abstract: Sn-doped Mn3O4/C nanocomposite was synthesized using Pluronics P123 (EO20PO70EO20) as both structure-directing agent and carbon source. The phase and morphology was characterized with X-ray diffraction (XRD), X-ray spectroscopy (EDS), Field-emission scanning electron microscope (FESEM) and transmission electron microscope (TEM). The electrochemical performance of the sample was tested in 6M KOH A high specific capacitance of 216Fg−1 was achieved at current density of 5Ag−1, and 93% capacitance retention remained after 10,000 charge/discharge cycles. [Copyright &y& Elsevier]

Abstract: NiCo2O4 nanowires-loaded reduced graphene oxide composite (NiCo2O4@RGO) was prepared by a facile hydrothermal method without any surfactant. Hexamethylenetetramine was introduced as a structure directing and assembling agent to the synthesis of NiCo2O4 nanowires. NiCo2O4 nanowires with an average size of 80×10nm2 are uniformly and densely dispersed on the graphene sheets. Cyclic voltammetry and galvanostatic charge–discharge measurements on NiCo2O4@RGO indicated a high specific capacitance of 737Fg−1 at a current density of 1Ag−1 and only 6% loss of the initial specific capacitance after 3000 charge/discharge cycles at 4Ag−1 in 2M KOH electrolyte, which is valuable for practical application in supercapacitors. [Copyright &y& Elsevier]

In this work, a core/shell structured polypyrrole@manganese dioxide (PPy@MnO 2) composite has been synthesized via one-step in-situ polymerization and subsequent hydrothermal method. [Display omitted] • PPy@MnO 2 with core/shell structure is synthesized via a simple strategy. • MnO 2 is the cross-linked continuous porous nanosheets shell in PPy@MnO 2. • The PPy@MnO 2 exhibits the highest specific capacitance of 614.7F·g−1 at 1.0 A·g−1. • The PPy@MnO 2 //AC device has achieved a satisfied energy density of 34.0 Wh·kg−1. The composition and structure are very critical to the property of electrode materials in supercapacitors. Herein, a core/shell polypyrrole@manganese dioxide (PPy@MnO 2) composite is prepared by a simple strategy. The electrode delivers the C s value of 614.7F·g−1 at 1.0 A·g−1, and exhibits outstanding rate performance in a three-electrode system. Moreover, asymmetric device (PPy@MnO 2 //AC) has been designed and possessed extraordinary rate performance, remarkable cycle stability, and the high energy density of 34.0 Wh·kg−1 at 317.6 W·kg−1. The core/shell structured PPy@MnO 2 delivers the excellent electrochemical performance, indicating its great application potential in supercapacitors. [ABSTRACT FROM AUTHOR]

Abstract: Highly uniform polyaniline-Ag nanocable arrays (NCAs) had been electrodeposited into the anodic aluminum oxide (AAO) template for supercapacitor studies. Each nanocable has the average values dimensions, with approximately length of 20μm and diameter of 100nm. The supercapacitor using PANI-Ag nanocable arrays as electrode showed excellent stability over a long cycle-life by cyclic voltammogram tests. The capacitance value of the electrode was as high as 850Fg−1 at 10mVs−1 sweep rate, and there was a decrease in capacitance with an increase of current density. These interesting results indicated that PANI-Ag NCAs could be an ideal alternative to carbon based electrodes, regular conducting polymers and metal oxides for the fabrication of supercapacitor. [Copyright &y& Elsevier]