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The carbon nanotubes attached mesoporous Ag3O4-coated NiO nanosheets were prepared successfully through hydrothermal method. The structural, morphological and electrochemical properties of the prepared nanocomposite have been studied. The X-ray diffraction and Raman analysis confirms the presence of NiO, Ag3O4 and carbon nanotubes in the prepared sample. HRTEM images clearly show the coating of Ag3O4 on the NiO and attachment of carbon nanotubes. BET surface area analysis confirms the mesoporous nature of the prepared composite. The cyclic voltammetric (CV), galvanostatic charge-discharge (GCD) and impedance analysis were made to explore the electrochemical nature of the composite. Cyclic voltammograms reveals the maximum specific capacity of 415.86 mAh g−1 at the scan rate of 3 mV s−1 and GCD analysis exhibits the specific capacity of 416.63 mAh g−1 at 1 A g−1. The prepared nanocomposite retained 97% of maximum capacity even after 1500 cycles. [ABSTRACT FROM AUTHOR]

Transition metal oxide-based magnetic nanocomposites attract great attention due to their unique properties and applications in the field of energy storage. Herein, we present a facile microwave procedure for the synthesis of CuFe2O4 (CF) and CuFe2O4 incorporated with reduced graphene oxide CuFe2O4/rGO (CG) as potential electrode materials for hybrid supercapacitor. The structure and morphology of CF and CG nanoparticles are examined. The electrochemical performance is studied in 6 M aqueous KOH electrolyte using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) techniques. The attractive CG nanocomposite exhibits high specific capacity of 800 C/g at a current density of 2 A/g and better cycling stability when compared to pure CF, due to the formation of nanostructure composed of ferrite nanoparticles homogeneously incorporated onto rGO sheets. Furthermore, the practicability of CG electrode is investigated by the fabrication of CG and activated carbon. The hybrid supercapacitor device shows excellent electrochemical performance with specific energy of 18.3 Wh/kg and a specific power of 455 W/kg. It is noteworthy that the cyclic stability is excellent with a capacity retention of ~98% after 3000 cycles manifesting the superiority of CG electrode. The proposed device demonstrates the potential to fabricate other metal oxides with activated carbon via a facile synthesis method for promoting application in energy storage materials and promoting new opportunities of binary nanocomposite. [ABSTRACT FROM AUTHOR]

The synthesis of bismuth based materials with porous structures for supercapacitor application has drawn much attention due to their high specific surface area and easy access of electrolytes with the electrode surface through their hierarchical pores. In this present report, we synthesized a three dimensional (3D) BiOCOOH micro flowers by a solvothermal approach and applied to supercapacitor applications. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy results confirmed that the formation of porous BiOCOOH flowers. When BiOCOOH was used as electrode material for supercapacitors it exhibits a maximum specific capacitance value of 312 F g−1 at current density of 1 Ag−1. Additionally, the BiOCOOH flowers retained 52% of its initial specific capacity after 5000 charge–discharge cycles indicating an excellent cyclic stability. This improvement in the cycle stability of the BiOCOOH is ascribed to high surface area and enhanced ion transport through the pores of the BiOCOOH flowers. This high specific capacitance and excellent cyclic stability of the porous BiOCOOH flowers prove to be a promising candidate for supercapacitor application. [ABSTRACT FROM AUTHOR]

Metal-doped tin oxide is gathering interest in the field of energy storage and power supply devices, particularly in supercapacitors applications. In the present study, we adopt a hydrothermal method to synthesis SnO2, Zn-SnO2, Ag-SnO2 nanoparticles at suitable conditions of temperature, pH, reaction time, and capping agents (CTAB). SnO2, Zn-SnO2, Ag-SnO2 nanoparticles were synthesized at 160 °C for 12 h and characterized by employing X-ray Diffraction to confirm the regular crystalline formation with tetragonal structure. Initial analyses by employing CV and GCD results exhibited specific capacitance of 308.2 Ag−1 for Ag-SnO2 nanoparticles at current density 0.5 A/g and can be considered as suitable candidate as positive electrode for supercapacitor device applications. [ABSTRACT FROM AUTHOR]

NiO/NiSnO3 nanocomposite synthesis was accomplished by a hydrothermal method. The role of polyvinylpyrrolidone and experimental parameters in the configuration of NiO/NiSnO3 nanocomposite was studied by employing standard characterization techniques. Electrochemical properties were demonstrated by adopting cyclic voltammetry, electro-impedance spectra and galvanostatic charging and discharging studies. All the obtained products have contact resistance Rct of 0.72 Ω at low frequency arising from the resistance between the working electrode and the electrolyte. The NiO/NiSnO3 nanocomposite superior properties may arise from nanosized rod morphology due to their inherent properties having a significant impact on their electrochemical properties. The specific capacitance for RSA3 can be estimated as 524 F/g at a current density of 0.5 A/g. [ABSTRACT FROM AUTHOR]

Size and shape controlled nickel oxide/nickel vanadate (NiO/Ni 3 V 2 O 8 ) nanocomposites were achieved by solvothermal method. Ammonium metavanadate and nickel chloride precursor solution in appropriate proportion was dissolved in solvent with sodium hydroxide as reducing and stabilizing agent. Three different products were obtained by varying solvothermal processing time as 10 h, 14 h and 18 h at 160 °C. X-ray diffraction (XRD), Fourier-transform infrared (FTIR), Raman and photo luminescence (PL) studies substantiate NiO/Ni 3 V 2 O 8 formation. Field emission scanning electron microscope (FESEM) studies provides detailed information about NiO/Ni 3 V 2 O 8 nanorods configuration. Electrochemical studies were carried out to understand pseudocapacitive properties of obtained products. Estimated specific capacitance for product PVK1 has superior value as 653 Fg −1 at current density 1 Ag −1 due to nanorods regular arrangement with uniform size distribution. [ABSTRACT FROM AUTHOR]

BiOI microsquares was prepared by using hexamine as surfactant through solvothermal approach and used as electrode material for high performance supercapacitor. The crystalline structure and morphology of the BiOI were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) analysis. The electrochemical performance was investigated by using cyclic voltametry (CV) and galvanostatic charge-discharge studies (GCD) using 6M KOH solutions. BiOI electrode exhibits highest specific capacitance of 706 Fg −1 at a current density of 2 Ag −1 . This material retained 55% initial capacitance at a higher current density of 10 Ag −1 indicating its better rate performance. [ABSTRACT FROM AUTHOR]

The three-dimensional (3D) floral-shaped V2O5was directly grown on Ni foam backbones by a straightforward and additive free hydrothermal approach. The as-synthesised material can be directly investigated as electrodes for supercapacitors without inclusion of other additives, such as polymer binder and carbon black. These elegant structural features endow this material with superior electrochemical features, such as high capacitance (601 Fg−1), superior withstanding capacity at higher rates (373 Fg−1at 5 Ag−1) and better cyclic stability. Most importantly, the symmetric supercapacitor using 3D-V2O5at Ni foam electrode exhibits specific capacitance of 142 Fg−1with energy density of 29 WhKg−1. Thirty light-emitting diodes were illuminated using three (connected in series) 3D-VN symmetric supercapacitors. Such impressive morphology and electrochemical richness of this material encourages its usefulness as supercapacitor electrodes. [ABSTRACT FROM PUBLISHER]

BiPO 4 nanomaterial was synthesized using EDTA (ethylene diamine tetra acetic acid) as the surfactant via a simple microwave method. The structure and morphology of BiPO 4 were systematically characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and scanning electron microscopy (FE-SEM) studies. The obtained BiPO 4 nanoparticles were, on average, 150–300 nm. The electrochemical results showed that the specific capacitance of BiPO 4 obtained using the microwave route was up to 104 Fg −1 at a current density of 1 Ag −1 with a large potential window of 1.7 V. The material showed excellent cycling stability (92% capacitance retention) after 500 cycles at a current density of 1 Ag −1 . [ABSTRACT FROM AUTHOR]

• Binder-free Star-like 3D-Co 3 O 4 /Ni forest positive electrode was synthesized via hydrothermal process. • Star-like 3D-Co 3 O 4 /Ni electrode exhibits high areal capacity of 143.28 mC cm−2 at 0.5 mA cm−2 with 88.4% retention. • Supercapattery device exhibited an energy density of 6.73 μWh cm−2 at power density of 700 μW cm−2. • 3D forest-like architecture results in better performance due to high surface area and porous nature in foot print area. [Display omitted] A binder-free positive electrode material of 3D starfish-like Co 3 O 4 /Ni forest is fabricated via a novel and facile hydrothermal process followed by thermal treatment. The morphological studies clearly showed the construction of starfish-like micro-flowers of Co 3 O 4 nanostructure forest densely covered on the entire Ni current collector. The 3D-Co 3 O 4 /Ni electrode displayed an areal capacity as high as 143.28 mC cm−2 at 0.5 mA cm−2 and higher stability of 88.4% after 5000 cycles. Moreover, the fabricated 3D-Co 3 O 4 /Ni||3D-Bi 2 O 3 /Ti s upercapattery delivered a maximum areal capacitance of 24.73 mF cm−2, the energy density of 6.73 μWh cm−2 and power density of 5250 μW cm−2 with good cycling stability> 71% capacity retention after 5000 cycles. The higher electrochemical performance of the electrode is delivered due to the availability of abundant electrochemically active sites in the 3D starfish-like Co 3 O 4 microflower, which facilitates a higher electrochemical reaction. The starfish-like forest architectures allow rapid ion diffusion, and the binder-free electrode reduces the contact resistance, which fasten the electron transport. These tolerable results prompt the as-prepared electrode with 3D starfish-like Co 3 O 4 microflower morphology as an auspicious positive electrode material for electrochemical energy storage devices. [ABSTRACT FROM AUTHOR]

• Square-shaped Bi 3 NbO 7 has been synthesized by the solvothermal approach. • Bi 3 NbO 7 electrode shows a high specific capacitance of 596 Fg−1. • Bi 3 NbO 7 has excellent cycle stability and specific capacitance. • The structure–property-performance correlation of the material is established. Herein Bi 3 NbO 7 micro squares were prepared by a simple solvothermal method, and their electrochemical performances towards supercapacitor application were assessed. XRD, Raman, XPS, FESEM and TEM analysis were performed as the confirmation studies for the Bi 3 NbO 7. The electrochemical measurements specified that the maximum specific capacitance value of 596 Fg−1 at a given current density of 2 Ag−1, and an outstanding cycling stability of ∼ 90 % capacitance retention over 2000 cycles at 10 Ag−1 were achieved. Hence, the single-component Bi 3 NbO 7 electrode material has been considered as alternate material for supercapacitor applications. [ABSTRACT FROM AUTHOR]

Bismuth-based semiconductors have attracted significant attention in rechargeable batteries and supercapacitor devices. In this study, layered structured bismuth germanate (Bi12GeO20) was synthesized using hexamine as a surfactant, at 850 °C, and utilized as electro-active material for supercapacitor and sodium ion (NaB) storage applications. The physical characterization of the prepared Bi12GeO20 was studied with various characterization and microscopic analyses such as XRD, FT-IR, FESEM with EDS, HRTEM, and XPS analysis. The XRD analysis exposed the successful formation of a highly crystalline sillenite phase of Bi12GeO20. The surface morphology analysis FE-SEM and HR-TEM revealed the effective construction of the 2D layered structure of Bi12GeO20. The EDS results profound that uniform distribution of the Bi, Ge, and O elements with good elemental stoichiometry. The supercapacitor properties of the prepared Bi12GeO20 were evaluated with the help of three electrode method using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance (EIS) techniques in the aqueous solution of 3.0 M KOH. The prepared Bi12GeO20 architecture shows a higher specific capacitance of 355 F g−1, with a current density of 1 A g−1. Finally, the sodium-ion storage capacity of Bi12GeO20 was evaluated using a coin cell-type electrode. The as-synthesized Bi12GeO20 material was utilized as an anode for Na ion storage and demonstrated a high specific capacity of 740 mAh g−1 at 0.1 C rate. With these appreciable electrochemical performances, the single component Bi12GeO20 holds an ideal alternative electrode material to develop high-performance power and energy storage devices. [ABSTRACT FROM AUTHOR]

• Involvement of Ca in DyMnO 3 parent matrix results in increased specific capacitance. • Novel perovskite composites for usage in battery-type electrodes in supercapacitor applications. • Battery-type electrode performance of the composite made into a device showed capacity retention of 76% The Multifaceted properties of nanostructured rare earth perovskite manganite oxides have attracted much attention specifically for their applications in energy storage systems. In the present work, synthesis and physiochemical properties of calcium-substituted dysprosium perovskite manganite oxide nanocomposites and their potential applications as supercapacitors are examined. The perovskite structure and morphology of the designed nanocomposites are affirmed by the different analytical tools, including XRD, SEM, and TEM analysis. The structural analysis by XRD indicates the presence of DyMnO 3 perovskite phase with additional peaks of Dy 2 O 3 phase. The percentage of Dy 2 O 3 is gradually reduced with higher Ca substitution, from about 16% to 7%. The Halder-Wagner method indicates an increase of the microstrain and a decrease in crystallite size with the rise of Ca substitution. From Tauc's plot derived from DRS analysis, a slight increase in the band gap with the increase in Ca substitution is observed (2.55–2.62 eV). The surface elemental compositions and the valence states of individual elements analyzed using XPS analysis evidence the presence of Dy, Ca, Mn, and O. BET adsorption study indicates an increase in pore size, surface area, and pore volume with increasing Ca substitution concentration. When employed as a supercapacitor electrode material, Calcium-blend DyMnO 3 nanocompositeexhibits battery type behavior. This material shows a higher specific capacitance (capacity) of 531 Fg−1 (319.9 Cg−1) with comparatively low charge transfer resistance and better cyclic stability. We have assembled an asymmetric supercapacitor device using our prepared sample exhibiting energy density of 36.16 Wh/kg with better cyclic stability. This work provides new insights for designing future Dy 2 O 3 based supercapacitors. [ABSTRACT FROM AUTHOR]

• Sm-MOF/rGO/PANI was synthesized via in situ oxidative polymerization. • Redox-active sites enabled solitary-MOFs based catalyzed by ternary composite using Sm-MOF/rGO/PANI are utilized for high-performance supercapacitors due to their high surface tunability. • Sm-MOF/rGO/PANI can be used as an electrode material for high-performance supercapacitors due to their high surface tunability. • The composite shows a high specific capacitance of 1935.6 f g-1 in a three-electrode setup. • The specific power and energy was calculated to be 581 Wh Kg−1 and 59.3 W Kg−1. In recent years, scientists have been paying a lot of attention to metal-organic frameworks, often known as MOFs, as a possible material for use as electrodes in supercapacitors. MOFs are capable of functioning as high-quality pseudocapacitors because of their crystalline structure, which enhances the specific surface area and provide mechanical support for composite materials. The objective of this study is to synthesize an electrode material that can be used as supercapacitors by synthesizing Sm-MOF and then combining it with reduced graphene oxide (rGO) and polyaniline (PANI) to make a hybrid material. Here, the effect of incorporation of PANI and rGO in Sm-MOF is investigated, and its application as a supercapacitor is examined. Due to the high surface area and pore size, Sm-MOF/rGO/PANI material exhibits high specific capacitance. The computed specific capacitance of the composite Sm-MOF/rGO/PANI material is 1935.6 F g−1 when subjected to a current density of 1 A g−1. The Sm-MOF/rGO/PANI device is fabricated and exhibits a specific capacitance of 218 F g−1. The specific power and energy are calculated to be 59.3 Wh kg−1 and 581 W kg−1, respectively. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Summarizing recent advances in the fabrication of stretchable supercapacitor. • The various experimental parameters, which used to design the stretchable electrode are summarized. • Various experimental approaches used to fabricate the stretchable supercapacitor are also discussed. • · Several structural designs of the stretchable electrodes with diverse electroactive materials are reviewed. • Challenges and future direction of stretchable supercapacitors were also discussed. In the modern phase of electricity and global connectivity, a supercapacitor plays an eye-catching role by overcoming the detrimental of capacitors and batteries. Imagining an advanced smartphone, a miniature, light-weight, flexible electronic device with good power and energy capability, large-scale stretchability, and self-healing property is one step ahead of becoming a reality in innovations. To facilitate the sustainable operation and ensure the reliability of the obtained electronic system, it is desirable to obtain satisfactory performance under certain conditions like bending, stretching, compressing, deforming and twisting, etc. However, multifunctional integrity remains a challenge in a single system. The stable and insistent output can only be possible by choosing the proper electrode design and material selection. This review discusses the recent trends in different categories of stretchable materials used for supercapacitor applications, various architectures influencing their stretchability, their mechanical properties like strain, pre-stretchability and healability, etc. and the usability of these stretchable materials in smart and wearable devices. [ABSTRACT FROM AUTHOR]

• Novel cost effective and greener microwave synthesis of Cu 2 O/MoS 2 /rGO is proposed. • Sheets of MoS 2 /rGO composite were wrapped over Cu 2 O nanoparticles for better performance. • Cu 2 MG exhibits enhanced supercapacitive behaviour with excellent cyclic stability. Novel Cu 2 O/MoS 2 /rGO nanostructure has been synthesized using simple and cost-effective microwave method. SEM and TEM observations confirm spherically-shaped Cu 2 O nanoparticles coated simultaneously with MoS 2 and rGO thin layers. The nanocomposite electrode exhibits high specific capacitance of 388F/g with excellent cyclic stability of 95.6% retained over 3000 charge–discharge cycles. The as-fabricated nanomaterial is a potential candidate for supercapacitor applications. [ABSTRACT FROM AUTHOR]