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A ferroelectric liquid crystal display device employs capacitance spoiling layers to minimize unneeded capacitances created by crossovers of X and Y address lines and to accurately define desired capacitances. The spoiler layers comprise low dielectric constant layers which space electrodes from the ferroelectric at crossover points where capacitance is not needed for device operation.
A generic design and a corresponding operating sequence have been developed for increasing the linear-response dynamic range of a complementary metal oxide/semiconductor (CMOS) image sensor. The design provides for linear calibrated dual-gain pixels that operate at high gain at a low signal level and at low gain at a signal level above a preset threshold. Unlike most prior designs for increasing dynamic range of an image sensor, this design does not entail any increase in noise (including fixed-pattern noise), decrease in responsivity or linearity, or degradation of photometric calibration. The figure is a simplified schematic diagram showing the circuit of one pixel and pertinent parts of its column readout circuitry. The conventional part of the pixel circuit includes a photodiode having a small capacitance, CD. The unconventional part includes an additional larger capacitance, CL, that can be connected to the photodiode via a transfer gate controlled in part by a latch. In the high-gain mode, the signal labeled TSR in the figure is held low through the latch, which also helps to adapt the gain on a pixel-by-pixel basis. Light must be coupled to the pixel through a microlens or by back illumination in order to obtain a high effective fill factor; this is necessary to ensure high quantum efficiency, a loss of which would minimize the efficacy of the dynamic- range-enhancement scheme. Once the level of illumination of the pixel exceeds the threshold, TSR is turned on, causing the transfer gate to conduct, thereby adding CL to the pixel capacitance. The added capacitance reduces the conversion gain, and increases the pixel electron-handling capacity, thereby providing an extension of the dynamic range. By use of an array of comparators also at the bottom of the column, photocharge voltages on sampling capacitors in each column are compared with a reference voltage to determine whether it is necessary to switch from the high-gain to the low-gain mode. Depending upon the built-in offset in each pixel and in each comparator, the point at which the gain change occurs will be different, adding gain-dependent fixed pattern noise in each pixel. The offset, and hence the fixed pattern noise, is eliminated by sampling the pixel readout charge four times by use of four capacitors (instead of two such capacitors as in conventional design) connected to the bottom of the column via electronic switches SHS1, SHR1, SHS2, and SHR2, respectively, corresponding to high and low values of the signals TSR and RST. The samples are combined in an appropriate fashion to cancel offset-induced errors, and provide spurious-free imaging with extended dynamic range.
A very high purity (99.99+%) high temperature co-fired ceramic (HTCC) alumina has recently become commercially available. The raw material of this HTCC alumina is very different from conventional HTCC alumina, and more importantly there is no glass additive in this alumina material for co-firing processing. Previously, selected HTCC and LTCC (low temperature co-fired ceramic) alumina materials were evaluated at high temperatures as dielectric and compared to a regularly sintered 96% polycrystalline alumina (96% Al2O3), where 96% alumina was used as the benchmark. A prototype packaging system based on regular 96% alumina with Au thickfilm metallization successfully facilitated long term testing of high temperature silicon carbide (SiC) electronic devices for over 10,000 hours at 500 C. In order to evaluate this new high purity HTCC alumina for possible high temperature packaging applications, the dielectric properties of this HTCC alumina substrate were measured and compared with those of 96% alumina and a previously tested LTCC alumina from room temperature to 550 C at frequencies of 120 Hz, 1 KHz, 10 KHz, 100 KHz, and 1 MHz. A parallel-plate capacitive device with dielectric of the HTCC alumina and precious metal electrodes were used for measurements of the dielectric constant and dielectric loss of the co-fired alumina material in the temperature and frequency ranges. The capacitance and AC parallel conductance of the capacitive device were directly measured by an AC impedance meter, and the dielectric constant and parallel AC conductivity of the dielectric were calculated from the capacitance and conductance measurement results. The temperature and frequency dependent dielectric constant, AC conductivity, and dissipation factor of the HTCC alumina substrate are presented and compared to those of 96% alumina and a selected LTCC alumina. Other technical advantages of this new co-fired material for possible high packaging applications are also discussed.
A very high purity (99.99+) high temperature co-fired ceramic (HTCC) alumina has recently become commercially available. The raw material of this HTCC alumina is very different from conventional HTCC alumina, and more importantly there is no glass additive in this co-fired material. Previously, selected HTCC and LTCC (low temperature co-fired ceramic) alumina materials were evaluated at high temperatures as dielectric and compared to a regularly sintered 96 polycrystalline alumina (96 Al2O3), where 96 alumina was used as the benchmark. A prototype packaging system based on regular 96 alumina with Au thick-film metallization successfully facilitated long term testing of high temperature silicon carbide (SiC) electronic devices for over 10,000 hours at 500C. In order to evaluate this new HTCC alumina for possible high temperature packaging applications, the dielectric properties of this HTCC alumina substrate were measured and compared with those of 96 alumina and a LTCC alumina from room temperature to 550C at frequencies of 120 Hz, 1 KHz, 10 KHz, 100 KHz, and 1 MHz. A parallel-plate capacitive device with dielectric of the HTCC alumina and precious metal electrodes were used for measurements of the dielectric constant and dielectric loss of the co-fired alumina material in the temperature and frequency ranges. The capacitance and AC parallel conductance of the capacitive device were directly measured by an AC impedance meter, and the dielectric constant and parallel AC conductivity of the dielectric were calculated from the capacitance and conductance measurement results. The temperature and frequency dependent dielectric constant, AC conductivity, and dissipation factor of the HTCC alumina substrate are presented and compared to those of 96 alumina. Other technical advantages of this new co-fired material for possible high packaging applications are also discussed.
A vibrating gyroscope includes a piezoelectric strip having length and width dimensions. The piezoelectric strip includes a piezoelectric material and carbon nanotubes (CNTs) substantially aligned and polled along the strip's length dimension. A spindle having an axis of rotation is coupled to the piezoelectric strip. The axis of rotation is parallel to the strip's width dimension. A first capacitance sensor is mechanically coupled to the spindle for rotation therewith. The first capacitance sensor is positioned at one of the strip's opposing ends and is spaced apart from one of the strip's opposing faces. A second capacitance sensor is mechanically coupled to the spindle for rotation therewith. The second capacitance sensor is positioned at another of the strip's opposing ends and is spaced apart from another of the strip's opposing faces. A voltage source applies an AC voltage to the piezoelectric strip.
A position measuring sensor formed from opposing sets of capacitor plates measures both rotational displacement and lateral displacement from the changes in capacitances as overlapping areas of capacitors change. Capacitances are measured by a measuring circuit. The measured capacitances are provided to a calculating circuit that performs calculations to obtain angular and lateral displacement from the capacitances measured by the measuring circuit.
Near-perfect space-charge neutralization is required for the transverse compression of high perveance ion beams for ion-beam-driven warm dense matter experiments, such as the Neutralized Drift Compression eXperiment (NDCX). Neutralization can be accomplished by introducing a plasma in the beam path, which provides free electrons that compensate the positive space charge of the ion beam. In this thesis, charge neutralization of a 40~keV, perveance-dominated Ar$^+$ beam by a Ferroelectric Plasma Source (FEPS) is investigated. First, the parameters of the ion beam, such as divergence due to the extraction optics, charge neutralization fraction, and emittance were measured. The ion beam was propagated through the FEPS plasma, and the effects of charge neutralization were inferred from time-resolved measurements of the transverse beam profile. In addition, the dependence of FEPS plasma parameters on the configuration of the driving pulser circuit was studied to optimize pulser design. An ion accelerator was constructed that produced a 30-50~keV Ar$^+$ beam with pulse duration $<$300~$\mu$s and dimensionless perveance $Q$ up to 8$\times$10$^{-4}$. Transverse profile measurements 33~cm downstream of the ion source showed that the dependence of beam radius on $Q$ was consistent with space charge expansion. It was concluded that the beam was perveance-dominated with a charge neutralization fraction of approximately zero in the absence of neutralizing plasma. Since beam expansion occurred primarily due to space charge, the decrease in effective perveance due to neutralization by FEPS plasma can be inferred from the reduction in beam radius. Results on propagation of the ion beam through FEPS plasma demonstrate that after the FEPS is triggered, the beam radius decreases to its neutralized value in about 5~$\mu$s. The duration of neutralization was about 10~$\mu$s at a charging voltage $V_{FEPS}$~=~5.5~kV and 35~$\mu$s at $V_{FEPS}$~=~6.5~kV. With $V_{FEPS}$~=~6.5~kV, the transverse current density profile 33~cm downstream of the source had a Gaussian shape with $x_{rms}$=5~mm, which corresponds to a half-angle divergence of 0.87$^\circ$. The measurements show that near-perfect charge neutralization with FEPS can be attained. No loss of ion beam current was detected, indicating the absence of a neutral cloud in the region of beam propagation, which would cause beam loss to charge exchange collisions. This provides evidence in favor of using FEPS in a future Heavy Ion Fusion accelerator. The FEPS discharge was investigated based on current-voltage measurements in the pulser circuit. Different values of series resistance and storage capacitance in the pulser circuit were used. The charged particle current emitted by the FEPS into vacuum was measured from the difference in forward and return currents in the driving circuit. It was found that FEPS is an emitter of negative charge, and that electron current emission begins approximately 0.5~$\mu$s after the fast-rising high voltage pulse is applied and lasts for tens of $\mu$s. The value of the series resistance in the pulser circuit was varied to change the rise time of the voltage pulse; plasma density was expected to decrease with increasing values of resistance. However, the data showed that changing the resistance had no significant effect. The average charge emitted per shot depends strongly on the value of the storage capacitance. Lowering the capacitance from 141~nF to 47~nF resulted in a near-complete shut-off of charge emission, although the amplitude of the applied voltage pulse was as high, and rise time as short, as when high-density plasma was produced. Increasing the capacitance from 141~nF to 235~nF increased the average charge emitted per shot by a factor of$~$2.
Graphene/Mn{sub 3}O{sub 4} nanocomposite is successfully synthesized from graphene oxide (GO)/MnO{sub 2} precursor using dilute hydrazine hydrate assisted hydrothermal reaction (DAH method). X-ray photoelectron spectroscopy (XPS) and Raman characterizations confirm the decrease of oxygen-containing functional groups of GO. The results indicate that GO have been reduced to graphene to a large degree to increase the electronic conductive channels. The morphology and the phase transformation of MnO{sub 2} can be ascribed to the “dissolution-recrystallization” mechanism. Such nanocomposite, as electrode material for supercapacitor, exhibits a high specific capacitance of 326.9 F g{sup −1}, almost 4 times that of GO/MnO{sub 2} precursor (81.3 F g{sup −1}). The good cycle stability of 94.6% capacitance retention after 1000 cycles, can be explained by the firm interfacial cohesion between graphene and Mn{sub 3}O{sub 4} nanoparticle. This soft chemical DAH process could be readily extended to the preparation of other classes of hybrids. - Graphical abstract: The phase transition can be explained by the “dissolution-recrystallization” model. The GO/MnO{sub 2} precursor is reduced into graphene/Mn{sub 3}O{sub 4} by the DAH process, and the electrochemical property is dramatically enhanced. - Highlights: • Graphene/Mn{sub 3}O{sub 4} nanocomposite is firstly synthesized successfully from GO/MnO{sub 2} precursor. • The phase transformation from MnO{sub 2} to Mn{sub 3}O{sub 4} has occurred. • The specific capacitance of the graphene/Mn{sub 3}O{sub 4} (326.9 F/g) is 4 times that of GO/MnO{sub 2} precursor.
Analysis the synergy among different components within graphene based asymmetric supercapacitor could help us to establish the criterion for construction the idea supercapacitor for real applications. For this purpose, 3D Networks for Fe{sub 2}O{sub 3} and α- Ni(OH){sub 2} individually/collectively decorated S-doped graphene composites were successfully synthesized. The electrochemical performances clearly indicate the multi-decorated composite possesses the largest specific capacitance, improved cycle stability and enhanced rate capability due to its efficient additive effect among the different components of supercapacitor. The pronounced high energy density, provided by redox-active transition mental oxide/hydroxide, combined with excellent conductivity, hydrophilia and efficient charge storage, originated from S-doped graphene, result in the excellent composite for asymmetric supercapacitor. Within the voltage range from 0 to 0.44 V versus Ag/AgCl, the specific capacitance of Fe{sub 2}O{sub 3} and Ni(OH){sub 2} co-decorated S-doped graphene composite can be achieved 2386 F g{sup −1} at current density of 1 A g{sup −1}. - Graphical abstract: The electrochemical performances clearly indicate the multi-decorated composite exhibits large specific capacitance, improved rate capability and long cycle stability due to its efficient additive effect among the different components of super-capacitor.
Carbon nanodot (C-dot) decorated V{sub 2}O{sub 5} (C-dot@V{sub 2}O{sub 5}) nanobelts are synthesized by single step, low cost hydrothermal route at low temperature by using V{sub 2}O{sub 5} and glucose as precursors. We have not added any extra organic solvents or surfactants which are commonly used for the preparation of different nanostructures of V{sub 2}O{sub 5}. Electron microscopy analyses demonstrate that C-dot is entrapped inside V{sub 2}O{sub 5} nanobelts which in turn enhance the conductivity and ion propagation property of this composite material. The C-dot@V{sub 2}O{sub 5} nanobelts exhibit an excellent three electrode electrochemical performance in 1 M Na{sub 2}SO{sub 4} and which showed a specific capacitance of 270 F g{sup −1} at 1 A g{sup −1}, which is ~ 4.5 times higher than the pristine V{sub 2}O{sub 5} electrode. The electrochemical energy storage capacity of this hybrid is investigated towards solid state supercapacitor application also for the first time by employing electrophoretically deposited C-dot as the counter electrode and Li based gel as the electrolyte. The hybrid material delivers an energy density of 60 W h kg{sup −1} and a reasonably high power density of 4.1 kW kg{sup −1} at 5 A g{sup −1} and good cycling stability and capacitance retention of about 87% was observed even after 5000 cycles. Above mentioned results clearly show that C-dot embedded hybrid, nanostructured transition metal oxides has great potential towards fabrication of electrodes for energy storage devices. - Highlights: • Synthesis of C-dot decorated V{sub 2}O{sub 5} by single step hydrothermal reduction method. • A specific capacitance of 270 F g{sup −1} at a current density of 1 A g{sup −1} for three electrode system. • Fabrication of solid state device by using gel electrolyte. • An energy density of 60 W h kg{sup −1} at 1 A g{sup −1} high power density of 4.1 kW kg{sup −1} at 5 A g{sup −1} for C-dot@V{sub 2}O{sub 5}.
The urgent need for sustainable development of human society has forced material scientists to explore novel materials starting from cheap natural precursors for next-generation energy storage devices by using environmentally friendly strategies. In this work, heteroatom-functionalized porous carbonaceous materials with 3D hierarchical and interconnected honeycomb-like structure have been successfully synthesized by using waste biomass pomelo peel as raw material through the combination of hydrothermal carbonization and followed KOH activation procedure. Benefiting from the unique honeycomb-like structure and high specific surface area, the as-obtained carbon material exhibits satisfactory capacitive behavior: 374 F/g at 0.1 A/g; excellent cycling stability of 92.5% capacitance retention over continuous 5000 cycles. More importantly, the as-assembled symmetric supercapacitors based on as-prepared electrode material can deliver high gravimetric and volumetric energy density of 20 W h/kg and 18.7 W h/L in 6 M KOH, respectively, as well as outstanding cycling stability. The obtained results demonstrate the possibility for taking full advantage of sustainable and large scale advanced carbon materials by choosing waste biomass, particularly the pomelo peel as a raw material. - Graphical abstract: 3D hierarchical and interconnected honeycomb-like porous carbonaceous materials (HPGC) from waste biomass (pomelo peels) were successfully prepared through the combination of hydrothermal carbonization and followed KOH activation procedure. The as-obtained carbon material exhibits satisfactory capacitive behavior. The obtained results demonstrate the possibility for taking full advantage of sustainable carbon materials by choosing biomass waste provided by nature as raw materials. Display Omitted - Highlights: • Pomelo peel was utilized to fabricate heteroatom-functionalized porous carbonaceous materials. • The as-prepared carbon materials contains 3D hierarchical and interconnected honeycomb-like structure. • The obtained carbon material and symmetric device exhibits superior electrochemical performances for supercapacitor.
Highlights: • A new facile liquid-phase method has been employed for synthesis boron-doped NiO nanoflowers. • The specific surface area of NiO is as high as 200 m{sup 2} g{sup −1}. • NiO nanoflowers exhibit a high specific capacitance of ∼1309 F g{sup −1} at a charge and discharge current density of 3 A g{sup −1}. • NiO nanoflowers have excellent cycling ability and even after 2500 cycles there is no significant reduction in specific capacitance. - Abstract: Boron-doped nickel oxide (B-NiO) nanoflowers are prepared by simple thermal decomposition of nickel hydroxide. B-NiO is porous sphere with a diameter of about 400 nm. B-NiO nanoflowers are composed of approximately 30 nm nanoplates and the thickness of the nanosheets is approximately 3 nm. The specific surface area of the material is as high as 200 m{sup 2} g{sup −1} and the pore size distribution curves of B-NiO has three typical peaks in the range of mesoporous (5 nm, 13 nm and 18 nm). As an electrode for supercapacitors, the crystalline B-NiO nanoflowers have favorable characteristics, for instance, a specific capacitance of 1309 F g{sup −1} at a current density of 3 A g{sup −1} and no significant reduction in Coulombic efficiency after 2500 cycles at 37.5 A g{sup −1}. This remarkable electrochemical performance will make B-NiO nanoflowers a promising electrode material for high performance supercapacitors.
Highlights: • Birnessite-type MnO{sub 2} nanoparticles were prepared by the microwave-assisted reflux. • The microwave reaction duration was only 5 min. • A specific capacitance of 329 F g{sup −1} was obtained for birnessite-type MnO{sub 2}. - Abstract: Birnessite-type MnO{sub 2} nanoparticles have been successfully synthesized by the microwave-assisted reflux as short as 5 min. The microstructure and morphology of the products were characterized by X-ray diffraction, N{sub 2} adsorption–desorption isotherms, scanning electron microscopy, transmission electron microscopy. The electrochemical properties of the as-prepared MnO{sub 2} as an electrode material for supercapacitor were investigated by cyclic voltammetry and galvanostatic charge-discharge measurements in 1 M Na{sub 2}SO{sub 4} electrolyte, and a high specific capacitance of 329 F g{sup −1} was achieved at a current density of 0.2 A g{sup −1}. The specific capacitance retention was 92% after 1000 cycles at 2 A g{sup −1}, suggesting that it is a promising electrode material for supercapacitors.
Highlights: • Novel Fe{sub 2}O{sub 3}/GP (graphene paper) negative electrode for supercapacitors was prepared. • The capacitance of Fe{sub 2}O{sub 3}/GP was ∼3.08 F cm{sup −2} at the density of 5 mA cm{sup −2}. • The Fe{sub 2}O{sub 3}/GP also showed good stability in long-term cyclic process. - Abstract: The development of Fe{sub 2}O{sub 3} with high conductivity and energy density is crucial for practical utilizations of supercapacitors. Here, we demonstrated the preparation of novel Fe{sub 2}O{sub 3}/graphene oxide paper (Fe{sub 2}O{sub 3}/GP) hybrid electrode for high density supercapacitors. Due to the characteristic features of large surface areas and fast electron transportation, the specific areal capacitance of the Fe{sub 2}O{sub 3}/GP was around 3.08 F cm{sup −2} at the charge-discharge current density of 5 mA cm{sup −2}, which is nearly 14 times of the Fe{sub 2}O{sub 3}/carbon paper (Fe{sub 2}O{sub 3}/CP, 0.22 F cm{sup −2}). More importantly, the Fe{sub 2}O{sub 3}/GP hybrid electrode also retained about 95% of the initial capacitance after long-term cyclic process. These findings would help us to develop high effective and stable materials for energy storage devices.
Highlights: • PPy were decorated on Co{sub 3}O{sub 4} nanowire surface via in-situ chemical polymerization. • Specific capacitance of 2122 F g{sup −1}at 5 mA cm{sup −2} was obtained. • The synergistic effect effectively enhanced electrochemical performance. - Abstract: Hierarchical Co{sub 3}O{sub 4}@ polypyrrole (PPy) core-shell composite nanowires (NWs) were successfully fabricated by a template-free hydrothermal route combined with in-situ chemical polymerization. Based on the composition and morphology characterization, it is found that the well-aligned Co{sub 3}O{sub 4} nanowires were uniformly coated with a thin layer of amorphous PPy. When directly used as an electrode material for supercapacitors, the Co{sub 3}O{sub 4}@PPy nanowire arrays exhibited high specific capacitance of 2122 F g{sup −1} (3.18 Fcm{sup −2}) at 5 mA cm{sup −2}, which is much higher than that of the pristine Co{sub 3}O{sub 4} nanowire arrays and improved cycling stability with 77.8% capacitance retention over 5000 cycles at 25 mA cm{sup −2}. The highly electronic conductive and electroactive PPy layer could significantly reduce charge transfer resistance and increase active sites. This synergistic strategy of the arrays structure and the PPy buffer layer can provide simple, efficient and versatile blue-prints for fabrication of Co{sub 3}O{sub 4}-based nanocomposites for extending its application for electrochemical energy storage.
Highlights: • A hollow shell coated on polypyrrole nanowires is constructed with the assistance of atomic layer deposition (ALD). • Binder-free electrode of holloe core-shell polypyrrole-TiO{sub 2} is obtained • The hollow core-shell nanostructure shows apparent higher capacitance and better cycling stability than the bare nanowires. - Abstract: Conducting polymers are promising electrode materials for electrochemical capacitors, but are suffered from poor cycling stability and relatively low capacitance. Herein, a hollow shell coated on polypyrrole (Ppy) nanowires is designed and constructed with the assistance of atomic layer deposition (ALD). Ppy nanowires are firstly deposited on flexible carbon cloth by electrodeposition, then a thin sacrificial layer of ZnO and a thin shell of TiO{sub 2} are deposited uniformly on the surfaces of the nanowires. After removing the ZnO layer, a nanogap between the Ppy core and TiO{sub 2} shell is formed thus generate a hollow core-shell Ppy-TiO{sub 2} (noted as Ppy·TiO{sub 2}) nanoarray. When tested as supercapacitor electrodes, the hollow core-shell nanostructure shows apparent higher capacitance and better cycling stability than the bare nanowires. Such enhancement is ascribed to the rational hollow structure design that provides enlarged surface areas and enhanced structure stability. Such hollow structure can be extended to other conducting polymers and electrodes for various electrochemical applications.
Highlights: • Activated biomass carbon (ABC) produced from bamboo was prepared by carbonization and KOH activation. • The BET and morphology of the ABC have a strong dependence on the activation temperature. • High specific capacitance along with durability is achieved. • Activated biomass carbon can serve as efficient electrode material for energy storage. - Abstract: Activated biomass carbons (ABC) produced from bamboo by carbonization and activation have high specific surface areas and mesoporous structures. The specific surface area, total pore volume, and average pore size of the activated biomass carbon are controlled by adjusting the activation temperature from 700 to 1000 °C. The carbon materials activated at 900 °C have an optimal mesoporous structure with a high specific surface area (2221.1 m{sup 2} g{sup −1}), the highest capacitance (293 F g{sup −1} at 0.5 A g{sup −1} in 3 M KOH aqueous electrolyte) and excellent rate capability (193.8 F g{sup −1} at 20 A g{sup −1}). Symmetric supercapacitors made of the optimal electrodes exhibit a high energy density of 10.9 Wh kg{sup −1} (18.2 Wh L{sup −1}) at a power density of 63 W kg{sup −1} (105 W L{sup −1}) and outstanding capacitance retention of 91.8% over 10,000 cycles. The high electrochemical performance of the mesoporous ABCs show that they are highly promising for energy-storage applications with further optimization.
Highlights: • The influence of pH, reaction time and temperature over the control of size of the spheres of SnO{sub 2} by hydrothermal method and further assembly over reduced graphene oxide has been carried out in this report. • The modification of SnO{sub 2} via (3- amino propyl triethoxysilane) makes the electrostatic self- assembly between the positively charged SnO{sub 2} nanostructure and the negatively charged graphene oxide (GO). • The impacts of concentration of GO added to SnO{sub 2} nanostructures and its significance on the morphology and the capacitive property of SnO{sub 2}/rGO composite are evaluated. • The functionalization of graphene enhances the capacitance as well as provides anchoring sites for the decoration by metal oxide nanostructures. - Abstract: Hydrothermally-synthesized, size and shape-controlled SnO{sub 2} nanospheres were electrostatically self-assembled over the surface of reduced graphene oxide (rGO). The control over decoration of SnO{sub 2} nanospheres on rGO was studied by microscopic analysis and the crystallographic structure of SnO{sub 2} hybrid nanocomposites (SnO{sub 2}: rGO) was determined from X-Ray diffraction analysis (XRD). Hybrid nanocomposite in 1:3 ratio exhibited (i) excellent methylene blue degradation capability within 3 min under visible light condition and (ii) high specific capacitance of 337.52 F/g at 0.5 A/g in 1 M H{sub 2}SO{sub 4} electrolyte with 89% of retention after 5000 cycles.