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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 973 records · Page 54
All sourcesNASA NTRSDOE OSTI
DOE OSTI2012

Supercapacitor behavior of α-MnMoO{sub 4} nanorods on different electrolytes

Graphical abstract: SEM image of α-MnMoO{sub 4} nanorods on FTO substrate. Highlights: ► Synthesis of α-MnMoO{sub 4} nanorods by spin coating method. ► First study on the effect of electrolyte on the pseudocapacitance behavior. ► α-MnMoO{sub 4} nanorods exhibit maximum specific capacitance of 998 F/g. ► At higher scan rates p-TSA electrolyte exhibits superior capacitive behavior. -- Abstract: α-MnMoO{sub 4} nanorods were prepared on conducting glass substrate via sol–gel spin coating method at the optimum doping level. The effect of electrolyte on the pseudocapacitance behavior of the α-MnMoO{sub 4} nanorods was studied using para toluene sulfonic acid (p-TSA), sulfuric acid (H{sub 2}SO{sub 4}) and hydrochloric acid (HCl) as electrolytes. X-ray diffraction analysis reveals the formation of α-MnMoO{sub 4} in monoclinic phase. FTIR spectra contain vibrational bands associated with Mo=O, M–O and Mo–O–Mo bonds. SEM image reveals the formation of nanorods. Supercapacitor behavior has been studied using cyclic voltammetry (CV) analysis. α-MnMoO{sub 4} nanorods exhibit maximum specific capacitance of 998 F/g at a scan rate of 5 mV/s in H{sub 2}SO{sub 4} electrolyte while a specific capacitance of 784 F/g and 530 F/g have been obtained using p-TSA and HCl electrolytes, respectively. At higher scan rates p-TSA electrolyte exhibits superior capacitive behavior than H{sub 2}SO{sub 4}.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Rational fabrication of carbon nanotubes arrays on porous nickel matrix as advanced electrode materials of supercapacitors

Highlights: • Construct self-supported porous Ni/CNTs composite arrays. • Porous Ni/CNTs arrays show superior capacitive performance. • Ni/CNTs arrays structure boosts fast electron/ion transfer. - Abstract: Rational synthesis of advanced carbon materials is of great importance to the development of supercapacitors. In this work, we propose a facile combined electrodeposition-chemical vapor deposition for tailored construction of carbon nanotubes (CNTs) arrays on highly porous Ni matrix forming integrated 3D Ni/CNTs electrode. Interconnected CNTs with diameters of 20–30 nm are strongly anchored on the cross-linked porous Ni branches consisting of nanoparticles of 500–600 nm. Capacitive performance of the obtained porous Ni/CNTs electrode is thoroughly characterized by electrochemical means including charge/discharge tests and cyclic voltammetry. The 3D Ni/CNTs electrode shows good high-rate performance with a capacitance of 186 F g{sup −1} at 2.5 A g{sup −1}, and excellent cycling stability with a capacitance retention of 99% after 10,000 cycles. The integrated conductive network composed of 3D Ni/CNTs offers large active area, good electronic conductivity and fast transportation paths of ions/electrons, leading to superior capacitive performance.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2020

Highly microporous Parinari Curatellifolia carbon nanomaterials for supercapacitors

High surface area nanostructured electrodes are essential for understanding charge storage mechanisms in high capacitance supercapacitors. Additionally, a growing number of studies provide credible evidence that the highest capacitance in carbon nanomaterials is attainable only when the pore size is in micropore range. In this study therefore, micropore-dominatedcarbon materials derived from Parinari curatellifolia (PC) waste seeds are prepared via pyrolysis and subsequent chemical activation with KOH. SEM, EDAX, TEM, Raman, and XRD studies show that the microstructure and composition of the as-prepared microporous carbon materials are influenced by adjusting the KOH to carbon mass ratio. Sorption studies demonstrate a very high BET surface area of 1898 m 2 g –1 , type I isotherm, and 99% micropore content in all the samples. The BET surface area, S micro , V micro , and total volume increased with increasing KOH content during activation. The fabricated electrodes exhibit high specific capacitances of 423 F g –1 at 5 mV s –1 and cyclic stability of 98% after 50000 cycles both of which are indicative of our carbon materials huge potential in making high performance supercapacitors. The specific capacitance increased with the micropore content in the samples signifying that the pores enhanced diffusion and hence the charge storage. The PC carbon materials deliver high specific capacitance due to the enhancement of diffusion and charge storage stemming from the synergetic interplay of the aforementioned textural parameters. As a result, the PC carbon materials therefore provide good prospects for supercapacitor applications.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2012

Revisiting plasma hysteresis with an electronically compensated Langmuir probe

The measurement of electron temperature in plasma by Langmuir probes, using ramped bias voltage, is seriously affected by the capacitive current of capacitance of the cable between the probe tip and data acquisition system. In earlier works a dummy cable was used to balance the capacitive currents. Under these conditions, the measured capacitive current was kept less than a few mA. Such probes are suitable for measurements in plasma where measured ion saturation current is of the order of hundreds of mA. This paper reports that controlled balancing of capacitive current can be minimized to less than 20 {mu}A, allowing plasma measurements to be done with ion saturation current of the order of hundreds of {mu}A. The electron temperature measurement made by using probe compensation technique becomes independent of sweep frequency. A correction of {<=}45% is observed in measured electron temperature values when compared with uncompensated probe. This also enhances accuracy in the measurement of fluctuation in electron temperature as {delta}T{sub pk-pk} changes by {approx}30%. The developed technique with swept rate {<=}100 kHz is found accurate enough to measure both the electron temperature and its fluctuating counterpart. This shows its usefulness in measuring accurately the temperature fluctuations because of electron temperature gradient in large volume plasma device plasma with frequency ordering {<=}50 kHz.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2015

Impedance analysis of Al{sub 2}O{sub 3}/H-terminated diamond metal-oxide-semiconductor structures

Impedance spectroscopy (IS) analysis is carried out to investigate the electrical properties of the metal-oxide-semiconductor (MOS) structure fabricated on hydrogen-terminated single crystal diamond. The low-temperature atomic layer deposition Al{sub 2}O{sub 3} is employed as the insulator in the MOS structure. By numerically analysing the impedance of the MOS structure at various biases, the equivalent circuit of the diamond MOS structure is derived, which is composed of two parallel capacitive and resistance pairs, in series connection with both resistance and inductance. The two capacitive components are resulted from the insulator, the hydrogenated-diamond surface, and their interface. The physical parameters such as the insulator capacitance are obtained, circumventing the series resistance and inductance effect. By comparing the IS and capacitance-voltage measurements, the frequency dispersion of the capacitance-voltage characteristic is discussed.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2015

Ion polarization behavior in alumina under pulsed gate bias stress

Alkali metal ion incorporation in alumina significantly increases alumina capacitance by ion polarization. With high capacitance, ion-incorporated aluminas become promising high dielectric constant (high-k) gate dielectric materials in field-effect transistors (FETs) to enable reduced operating voltage, using oxide or organic semiconductors. Alumina capacitance can be manipulated by incorporation of alkali metal ions, including potassium (K{sup +}), sodium (Na{sup +}), and lithium (Li{sup +}), having different bond strengths with oxygen. To investigate the electrical stability of zinc tin oxide-based transistors using ion incorporated alumina as gate dielectrics, pulsed biases at different duty cycles (20%, 10%, and 2% representing 5 ms, 10 ms, and 50 ms periods, respectively) were applied to the gate electrode, sweeping the gate voltage over series of these cycles. We observed a particular bias stress-induced decrease of saturation field-effect mobility accompanied by threshold voltage shifts (ΔV{sub th}) in potassium and sodium-incorporated alumina (abbreviated as PA and SA)-based FETs at high duty cycle that persisted over multiple gate voltage sweeps, suggesting a possible creation of new defects in the semiconductor. This conclusion is also supported by the greater change in the mobility-capacitance (μC) product than in capacitance itself. Moreover, a more pronounced ΔV{sub th} over shorter times was observed in lithium-incorporated alumina (abbreviated as LA)-based transistors, suggesting trapping of electrons in existing interfacial states. ΔV{sub th} from multiple gate voltage sweeps over time were fit to stretched exponential forms. All three dielectrics show good stability using 50-ms intervals (20-Hz frequencies), corresponding to 2% duty cycles.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2015

Generation of a pulsed low-energy electron beam using the channel spark device

For the generation of low-energy electron beam, the design and characteristics of channel spark discharge (CSD) operating at a low voltage are presented in this paper. The discharge voltage, discharge current, X-ray emissions, and electron beam current were experimentally determined. The effects of the applied voltage, working gas pressure, and external capacitance on the CSD and beam parameters were measured. At an applied voltage of 11 kV, an oxygen gas pressure of 25 mTorr, and an external capacitance of 16.45 nF, the maximum measured current was 900 A. The discharge current increased with the increase in the pressure and capacitance, while its periodic time decreased with the increase in the pressure. Two types of the discharge were identified and recorded: the hollow cathode discharge and the conduction discharge. A Faraday cup was used to measure the beam current. The maximum measured beam current was 120 A, and the beam signal exhibited two peaks. The increase in both the external capacitance and the applied discharge voltage increased the maximum electron beam current. The electron-beam pulse time decreased with the increase in the gas pressure at a constant voltage and increased with the decrease in the applied discharge voltage. At an applied voltage of 11 kV and an oxygen gas pressure of 15 mTorr, the maximum beam energy was 2.8 keV. The X-ray signal intensity decreased with the increase in the gas pressure and increased with the increase in the capacitance.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

Memcapacitive characteristics in reactive-metal (Mo, Al)/HfO{sub X}/n-Si structures through migration of oxygen by applied voltage

Memcapacitive characteristics were investigated in metal-oxide-semiconductor (MOS) structure of reactive electrode (Mo, Al) and hafnium oxide (HfO{sub X}) on n-type Si substrate. The capacitance-voltage curves exhibited sequentially changing capacitance with memory function as repeating voltage sweeps, featured the memcapacitive behaviors. The saturation capacitance was decreased by repeating +V sweeps, while barely changed by −V sweeps. Also, the capacitance-time curves disclosed the same tendency. However, the MOS structure with inert Pt electrode did not show the capacitance change. The memcapacitive behaviors were induced by the migration of oxygen ions from HfO{sub X} to reactive electrodes by applied voltage, which altered the permittivity of HfO{sub X}.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2016

Note: Expanding the bandwidth of the ultra-low current amplifier using an artificial negative capacitor

The bandwidth and low noise characteristics are often contradictory in ultra-low current amplifier, because an inevitable parasitic capacitance is paralleled with the high value feedback resistor. In order to expand the amplifier’s bandwidth, a novel approach was proposed by introducing an artificial negative capacitor to cancel the parasitic capacitance. The theory of the negative capacitance and the performance of the improved amplifier circuit with the negative capacitor are presented in this manuscript. The test was conducted by modifying an ultra-low current amplifier with a trans-impedance gain of 50 GΩ. The results show that the maximum bandwidth was expanded from 18.7 Hz to 3.3 kHz with more than 150 times of increase when the parasitic capacitance (∼0.17 pF) was cancelled. Meanwhile, the rise time decreased from 18.7 ms to 0.26 ms with no overshot. Any desired bandwidth or rise time within these ranges can be obtained by adjusting the ratio of cancellation of the parasitic and negative capacitance. This approach is especially suitable for the demand of rapid response to weak current, such as transient ion-beam detector, mass spectrometry analysis, and fast scanning microscope.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

On the theory of electric double layer with explicit account of a polarizable co-solvent

We present a continuation of our theoretical research into the influence of co-solvent polarizability on a differential capacitance of the electric double layer. We formulate a modified Poisson-Boltzmann theory, using the formalism of density functional approach on the level of local density approximation taking into account the electrostatic interactions of ions and co-solvent molecules as well as their excluded volume. We derive the modified Poisson-Boltzmann equation, considering the three-component symmetric lattice gas model as a reference system and minimizing the grand thermodynamic potential with respect to the electrostatic potential. We apply present modified Poisson-Boltzmann equation to the electric double layer theory, showing that accounting for the excluded volume of co-solvent molecules and ions slightly changes the main result of our previous simplified theory. Namely, in the case of small co-solvent polarizability with its increase under the enough small surface potentials of electrode, the differential capacitance undergoes the significant growth. Oppositely, when the surface potential exceeds some threshold value (which is slightly smaller than the saturation potential), the increase in the co-solvent polarizability results in a differential capacitance decrease. However, when the co-solvent polarizability exceeds some threshold value, its increase generates a considerable enhancement of the differential capacitance in a wide range of surface potentials. We demonstrate that two qualitatively different behaviors of the differential capacitance are related to the depletion and adsorption of co-solvent molecules at the charged electrode. We show that an additive of the strongly polarizable co-solvent to an electrolyte solution can shift significantly the saturation potential in two qualitatively different manners. Namely, a small additive of strongly polarizable co-solvent results in a shift of saturation potential to higher surface potentials. On the contrary, a sufficiently large additive of co-solvent shifts the saturation potential to lower surface potentials. We obtain that an increase in the co-solvent polarizability makes the electrostatic potential profile longer-ranged. However, increase in the co-solvent concentration in the bulk leads to non-monotonic behavior of the electrostatic potential profile. An increase in the co-solvent concentration in the bulk at its sufficiently small values makes the electrostatic potential profile longer-ranged. Oppositely, when the co-solvent concentration in the bulk exceeds some threshold value, its further increase leads to decrease in electrostatic potential at all distances from the electrode.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2014

Design and development of line type modulators for high impedance electron gun

Conventional line type modulators are routinely used for powering pulsed power microwave devices such as magnetrons and klystrons used for radar, medical and scientific applications. The load impedance (operating point) is fairly well defined in these cases, and makes the design of the discharging circuit of the modulator straight forward. This paper describes the Line type modulators that have been developed and being routinely used for powering the Triode Electron Gun of industrial electron linacs. The beam parameters of such guns are user defined and the pulse current varies from few mA to 800mA (typ). The beam energies requirement varies from 40 keV to 80 keV. Hence the impedance offered by the electron gun to the power source (modulator) is not well defined. The load capacitance which is inclusive of the various stray capacitances along with the intrinsic gun capacitance is ∼ 200-400 pF. This capacitance, which depends on the configuration, shunts the load and makes the effective load highly capacitive with the resistive part varying over a wide range. The paper describes the design and development of conventional line type modulators for powering Electron gun load of the type described above. (author)

43 PARTICLE ACCELERATORS↗
DOE OSTI2018

Hybrid Graphene Ribbon/Carbon Electrodes for High‐Performance Energy Storage

Abstract The utility of supercapacitors for both fixed and portable energy storage would be greatly enhanced if their energy density could be increased while maintaining their high power density, fast charging time, and low cost. This study describes a simple, solution‐phase, scalable modification of carbon materials by a covalently bonded “brush” of hydrogen‐terminated graphene ribbons (GRs) with layer thicknesses of 2–20 nm, resulting in a 20–100 times increase in the areal capacitance of the unmodified electrode surface. On a flat sp 2 carbon surface modified by GRs, the capacitance exceeds 1200 µF cm −2 in 0.1 m H 2 SO 4 due to a distinct type of pseudocapacitance during constant current charge/discharge cycling. Modification of high surface area carbon black electrodes with GRs yields capacitances of 950–1890 F g −1 , power densities >40 W g −1 , and minimal change in capacitance during 1500 charge/discharge cycles at 20 A g −1 . A capacitance of 1890 F g −1 affords an energy density of 318 Wh kg −1 operating at 1.1 V and 590 Wh kg −1 at 1.5 V. The projected energy density of a hybrid GR/carbon supercapacitor greatly exceeds the current 10 Wh kg −1 for commercial supercapacitors and approaches that of lithium ion batteries.

Farquhar, Anna K.↗
DOE OSTI2016

Fabrication of ultrafine manganese oxide-decorated carbon nanofibers for high-performance electrochemical capacitors

Ultrafine manganese oxide-decorated carbon nanofibers (MnOn-CNF) as a new type of electrode materials are facilely fabricated by direct conversion of Mn, Zn-trimesic acid (H3BTC) metal organic framework fibers (Mn-ZnBTC). The construction and evolution of Mn-ZnBTC precursors are investigated by SEM and in situ high-energy XRD. The manganese oxides are highly dispersed onto the porous carbon nanofibers formed simultaneously, verified by TEM, X-ray absorption fine structure (XAFS), Raman, ICP-AES and N2 adsorption techniques. As expected, the resulting MnOn-CNF composites are highly stable, and can be cycled up to 5000 times with a high capacitance retention ratio of 98% in electrochemical capacitor measurements. They show a high capacitance of up to 179 F g–1 per mass of the composite electrode, and a remarkable capacitance of up to 18290 F g–1 per active mass of the manganese(IV) oxide, significantly exceeding the theoretical specific capacitance of manganese(IV) oxide (1370 F g–1). The maximum energy density is up to 19.7 Wh kg–1 at the current density of 0.25 A g–1, even orders higher than those of reported electric double-layer capacitors and pseudocapacitors. The excellent capacitive performance can be ascribed to the joint effect of easy accessibility, high porosity, tight contact and superior conductivity integrated in final MnOn-CNF composites.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2012

Liquid crystalline phase synthesis of nanoporous MnO{sub 2} thin film arrays as an electrode material for electrochemical capacitors

Graphical abstract: Three-dimensional (3D) MnO{sub 2} thin film arrays with nanoporous structure is electrodeposited on Ti foil from hexagonal lyotropic liquid crystalline phase. Low-angle X-ray diffraction (XRD), wide-angle XRD, field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) are employed to study the morphology and the structure of the as-synthesized MnO{sub 2} materials. Galvanostatic charge/discharge measurements show the nanoporous, 3D electrode material exhibits excellent capacitive performance between the potential range of −0.1 to 0.9 V, and a maximum specific capacitance as high as 462 F g{sup −1} are achieved in 0.5 M Na{sub 2}SO{sub 4} solution at a charge/discharge current density of 4 A g{sup −1}. Highlights: ► 3D MnO{sub 2} thin film arrays with nanoporous structure is fabricated for the first time. ► A maximum specific capacitance as high as 462 F g{sup −1} is obtained. ► The 3D and nanoporous superarchitecture facilitate electrolyte penetration. -- Abstract: Three-dimensional (3D) MnO{sub 2} thin film arrays with nanoporous structure is electrodeposited on Ti foil from hexagonal lyotropic liquid crystalline phase. Low-angle X-ray diffraction (XRD), wide-angle XRD, field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) are employed to study the morphology and the structure of the as-synthesized MnO{sub 2} materials. Galvanostatic charge/discharge measurements show the nanoporous, 3D electrode material exhibits excellent capacitive performance between the potential range of −0.1 to 0.9 V, and a maximum specific capacitance as high as 462 F g{sup −1} are achieved in 0.5 M Na{sub 2}SO{sub 4} solution at a charge/discharge current density of 4 A g{sup −1}.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Supercapacitive properties of hydrothermally synthesized sphere like MoS{sub 2} nanostructures

Highlights: • MoS{sub 2} nanostructures were synthesized by hydrothermal method. • Randomly stacked MoS{sub 2} was obtained. • FE-SEM studies show the sphere like morphology of MoS{sub 2}. • Specific capacitance of 92.85 F/g was achieved using charge–discharge analysis. • MoS{sub 2} electrode shows capacitance retention of about 93.8% after 1000 cycles. - Abstract: In this communication, we have investigated the supercapacitive behaviour of MoS{sub 2} nanostructures prepared by a facile one-pot hydrothermal approach using ammonium heptamolybdate and thiourea as starting materials. The X-ray diffraction study revealed the formation of randomly stacked layers of MoS{sub 2}. The field-emission scanning electron microscope studies suggested the formation of sphere like MoS{sub 2} nanostructures and a plausible mechanism for the formation of the obtained structure is discussed. The cyclic voltammetry study shows the typical rectangular shaped curves with a specific capacitance of 106 F/g at a scan rate of 5 mV/s. Galvanostatic charge–discharge measurements suggested the maximum specific capacitance of about 92.85 F/g at discharge current density of 0.5 mA/cm{sup 2}. Cyclic stability tests revealed the capacitance retention of about 93.8% after 1000 cycles suggesting a good cyclic capacity of the prepared MoS{sub 2}. The electrochemical impedance spectroscopic results such as Nyquist and Bode phase angle plots suggested that the hydrothermally synthesized MoS{sub 2} nanostructures will be a suitable candidate for electrochemical supercapacitor applications.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Interplay between Ion Transport, Applied Bias, and Degradation under Illumination in Hybrid Perovskite p-i-n Devices

In this work, we studied ion transport in hybrid organic–inorganic perovskite p-i-n devices as a function of applied bias under device operating conditions. Using electrochemical impedance spectroscopy (EIS) and equivalent circuit modeling, we elucidated various resistive and capacitive elements in the device. We show that ion migration is predictably influenced by a low applied forward bias, characterized by an increased capacitance at the hole-transporting (HTM) and electron-transporting material (ETM) interfaces, as well as in bulk. However, unlike observations in n-i-p devices, we found that there is a capacitive discharge leading to ion redistribution in the bulk at high forward biases. Furthermore, we show that a chemical double-layer capacitance buildup as a result of ion accumulation impacts the electronic properties of the device, likely by inducing either charge pinning or charge screening, depending on the direction of the ion-induced field. Finally, we extrapolate ion diffusion coefficients (~10 –7 cm 2 s –1 ) and ionic conductivities (~10 –7 S cm –1 ) from the Warburg mass (ion) diffusion response and show that, as the device degrades, there is an overall depletion of capacitive effects coupled with increased ion mobility.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Understanding the MXene Pseudocapacitance

MXenes have attracted great attention as next-generation capacitive energy-storage materials, but the mechanisms underlying their pseudocapacitive behavior are not well understood. Here we provide a theoretical description of the surface redox process of Ti3C2Tx (T = O, OH), a prototypical MXene, in 1 M H2SO4 electrolyte, based on joint density functional theory with an implicit solvation model and the analysis of Gibbs free energy under a constant-electrode potential. From the dependence of the O/OH ratio (or the surface H coverage) and the surface charge on the applied potential, we obtain a clear picture of the capacitive energy-storage mechanism of Ti3C2Tx that shows good agreement with previous experimental findings in terms of the integral capacitance and Ti valence change. We find a voltage-dependent redox/double-layer co-charging behavior: the capacitive mechanism is dominated by the redox process, but the electric double-layer charge works against the redox process. This new insight may be useful in improving the capacitance of MXenes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Self-Assembly of Monodisperse Starburst Carbon Spheres into Hierarchically Organized Nanostructured Supercapacitor Electrodes

We report a three-dimensional (3D) porous carbon electrode containing both nanoscale and microscale porosity, which has been hierarchically organized to provide efficient ion and electron transport. The electrode organization is provided via the colloidal self-assembly of monodisperse starburst carbon spheres (MSCSs). The periodic close-packing of the MSCSs provides continuous pores inside the 3D structure that facilitate ion and electron transport (electrode electrical conductivity ~0.35 S m –1 ), and the internal meso- and micropores of the MSCS provide a good specific capacitance. Here, the capacitance of the 3D-ordered porous MSCS electrode is ~58 F g –1 at 0.58 A g –1 , 48% larger than that of disordered MSCS electrode at the same rate. At 1 A g –1 the capacitance of the ordered electrode is 57 F g –1 (95% of the 0.24 A g –1 value), which is 64% greater than the capacitance of the disordered electrode at the same rate. The ordered electrode preserves 95% of its initial capacitance after 4000 charging/discharging cycles.

25 ENERGY STORAGE↗