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Results for “Supercapacitor”

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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Calorimetry can detect the early onset of hydrolysis in hybrid supercapacitors with aqueous electrolytes

This study investigates the effect of cation species on the onset of electrolyte hydrolysis in hybrid supercapacitors with aqueous electrolytes using isothermal operando calorimetry. The cells consisted of a positive α-MnO 2 cryptomelane electrode and a negative activated carbon (AC) electrode with either 0.5 M K 2 SO 4 or 0.5 M Cs 2 SO 4 aqueous electrolytes. They were characterized using cyclic voltammetry and galvanostatic cycling. In addition, the instantaneous heat generation rate at each electrode was measured using a custom isothermal operando calorimeter. Heat generation associated with resistive losses (Joule heating) and reversible ion adsorption/desorption was clearly identified. For larger potential windows, an endothermic dip, attributed to the onset of hydrolysis, was observed at the positive α-MnO 2 electrode where K + and Cs + ions engaged in fast surface redox reactions. Interestingly, this endothermic dip appeared at 1.8 V and 2.0 V for K 2 SO 4 and Cs 2 SO 4 aqueous electrolytes, respectively. The difference in the stable operating potential window was attributed to thinner solvation shell around Cs + cation than for K + thus reducing the amount of water present near the electrodes as ions partially shed their solvation shells during adsorption. The early onset of hydrolysis could be observed by isothermal operando calorimetry before it could be observed with conventional electrochemical methods.

42 ENGINEERING↗
DOE OSTI2025

Wastepaper-derived porous carbon supported cobalt nanocomposites for all solid-state flexible supercapacitor

The conversion of wastepaper into high-value carbon materials has gained significant attention as a sustainable strategy for energy storage applications. Owing to its low cost, abundance, and intrinsic fibrous structure, wastepaper serves as an attractive precursor for carbon-based electrode materials. In this work, a novel electrode comprising cobalt nanoparticles and Co 3 O 4 embedded in wastepaper-derived porous carbon has been developed for use in a flexible all-solid-state asymmetric supercapacitor. The integration of cobalt nanoparticles and Co 3 O 4 introduces redox-active centres, which enhance the electrochemical activity of the carbon framework. Mean while, the interconnected porous and conductive carbon network enables rapid ion diffusion and efficient electron transport, synergistically improving the overall electrochemical performance. It delivers a high specific capacitance of 61.5 Fg -1 , a power density of 5143 W kg -1 , and an energy density of 9 Wh kg -1 at a current density of 2.5 A/ g. Furthermore, the device maintains outstanding cycling stability, retaining 82.86 % of its capacitance after 10,000 charge-discharge cycles. Practical applicability is confirmed through its ability to power

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Engineered MXene quantum dots for micro-supercapacitors with excellent capacitive behaviors

Micro-supercapacitors (MSCs) have drawn tremendous attention as promising candidates to power miniaturized portable/wearable electronics, but they still suffer from unsatisfactory electrochemical performance (e.g., insufficient energy density, mediocre rate capability), thus impeding their widespread applications. Here, a synergistic surface and structure engineering strategy achieved by downsizing to quantum dot scale, doping of heteroatoms, and introducing defects and functional groups is proposed to regulate the physicochemical properties of Ti 3 C 2 T x MXene. Encouragingly, the resulting MSCs based on defect-rich nitrogen-doped Ti 3 C 2 T x quantum dots (QDs) possess excellent electrochemical performance as demonstrated by large operating voltage (3.0 V in ionic liquid and 1.0 V in aqueous electrolyte), perfect rectangular CV shape even at 1000 V·s -1 , high volumetric capacitance of 33.1 F·cm -3 , and superior cycling stability after 10000 cycles. By employing experimental characterizations and density functional theory calculations, the remarkable performance of the MSCs is mainly due to the special chemical states as well as the unique surface and structural features of Ti 3 C 2 T x QDs, which offer abundant active sites, shorten ion diffusion pathways, promote ion/electron transports, and provide enhanced capacitance. Finally, this work provides a new strategy for the design of high-performance MSCs and a reference for the applications of MXene QDs in other energy-related fields.

42 ENGINEERING↗
DOE OSTI2023

Solid-state polymer magnesium supercapacitor

Here, the present article focuses on the development of a highly ion-conductive, solvent-free, solid-state polymer electrolyte membrane (PEM) via photopolymerization of polyethylene glycol diacrylate (PEGDA) network from its homogeneous melt mixtures containing succinonitrile (SCN) plasticizer and magnesium bis(trifluoromethane sulfonyl) imide Mg(TFSI) 2 salt. The above solid-state Mg-PEM exhibits a Helmholtz electric double-layer capacitor (EDLC) behavior in its supercapacitive symmetric carbonaceous electrode configuration. The electrochemical stability for this PEM membrane (20/40/40 PEGDA/SCN/Mg (TFSI) 2 ) was found to be approximately 3 V from linear sweep voltammetry with a specific capacitance of about 44 F/g from cyclic voltammetry and an energy density of approximately 17 Wh/kg in the 0–2 V range from the constant current density (CCD) experiment. Of particular interest is its excellent capacity retention of over 11,200 cycles, thus tested with the Coulombic efficiency of over 87%. Moreover, the energy density after extensive cycling for 11,200 has increased to approximately 56 Wh/kg at 10 mV/s in the potential range of 0–3 V relative to 17 Wh/kg in the potential range of 0–2 V at the same scan rate, attesting the excellent electrochemical stability and long life of the present Mg-PEM supercapacitor.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2021

Economic Comparison Between Battery and Supercapacitor for Hourly Dispatching Wave Energy Converter Power

This paper demonstrates a dispatching scheme of slider-crank wave energy converter (WEC) power generation using two different kinds of energy storage components, namely, Lithium-ion (Li-ion) battery and Supercapacitors (SC). The performance of the two energy storage components has been compared in order to develop the most economical energy storage system for WEC hourly dispatching scheme. The cost optimization of the energy storage system considering both cycling and calendar aging expenses is made based on its usage of depth of discharge. In this study, extensive simulation is conducted in MATLAB/Simulink platform, and it is found that SC is a better solution than Li-ion battery in terms of economic assessment for hourly dispatching WEC power.

50 EE - Wind and Water Power Program - Water (EE-4↗
DOE OSTI2021

Electrochemical and In Situ Spectroscopic Study of the Effect of Prussian Blue as a Mediator in a Solid-State Supercapacitor

In situ X-ray absorption spectroscopy (XAS) along with electrochemical measurements were used to explore the redox activity of Prussian blue (PB) and its contribution to pseudocapacitance in an asymmetrical solid-state supercapacitor (SC). The SC, with a configuration of (activated carbon)/polymer electrolyte membrane/(activated carbon + PB), was fabricated with an embedded KCl saturated Ag/AgCl reference electrode. The potentials of the two electrodes were generally displaced proportionally with increase in the cell voltage. Upon negative polarization from the open circuit voltage (OCV) condition to -3 V, the charge capacity was greater than that upon positive polarization from the OCV condition to +3 V, in agreement with the higher fraction of Fe(III) than that of Fe(II) and the low concentration of K ions in PB. Detailed analysis of cyclic voltammetry data in the range between 0 and -3 V indicates that the battery-like contribution to the charge current was 96% that of the capacitor-like contribution at a scanning rate of 2.5 mV s -1 but only 15% at 100 mV s -1 . The in situ XAS characterization results indicate that the majority of Fe was reversibly charged and discharged between Fe(III) and Fe(II) during positive and negative polarizations with minimal changes in local atomic structure.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Hybrid Mesoporous Carbon/Copper Ferrite Electrode for Asymmetric Supercapacitors

Asymmetric supercapacitors (ASCs) with two dissimilar electrodes are known to exhibit relatively moderate energy and power densities. If electrodes derived from earth-abundant materials or renewable resources such as lignocellulosic biomass (LCB) are used for fabrication, energy storage systems are expected to become less expensive and more sustainable. Hybrid electrode materials have advantages such as higher surface area, better chemical stability, and superior energy density. This study reports on the synthesis of a novel hybrid electrode material containing porous carbon (POC) and copper ferrite, which is designated as POC@Cu-ferrite, and its electrochemical performance in ASC configuration. Corn stover derived hydrochar is utilized for the sol–gel synthesis of POC@Cu-ferrite hybrid material using earth-abundant Cu and Fe-based precursors. This material is characterized using X-ray diffraction (XRD), Raman spectroscopy, Brunauer–Emmett–Teller (BET) surface area analyzer, and scanning and transmission electron microscopy (SEM/TEM). As-synthesized Cu-ferrite is found to contain 89.2% CuFe 2 O 4 and 10.8% Fe 2 O 3 , whereas other phases such as Fe 3 O 4 , CuFeO 2 , and CuO are observed for the POC@Cu-ferrite. BET-specific surface area (SSA) and pore volume of POC@Cu-ferrite are observed as 1068 m 2 /g and 0.72 cm 3 /g, respectively. POC@Cu-ferrite hybrid electrode is used with POC opposite electrode to fabricate ASC, which is tested using Gamry G-300 potentiostat/galvanostat/ZRA to obtain cyclic voltammetry (CV) profiles and galvanostatic charge–discharge (GCD) plots. ASC is also prepared using Cu-ferrite and POC materials and its specific capacitance and stability are compared with ASCs prepared with POC@Cu-ferrite and POC or graphene nanoplatelets (GNPs) electrodes. POC@Cu-ferrite hybrid electrode is found to be superior with a 2-fold higher capacitance and significant electrochemical stability over 100 GCD cycles as compared to the Cu-ferrite electrode.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Economic Comparison Between a Battery and Supercapacitor for Hourly Dispatching Wave Energy Converter Power: Preprint

This paper demonstrates a successful dispatching scheme of slider-crank wave energy converter (WEC) production using two different kinds of energy storage systems, namely, (i) Li-ion battery and (ii) Supercapacitors (SC). The performance of two energy storage systems has been compared in order to develop the most economical energy storage system for WEC hourly dispatching scheme. The cost optimization of the energy storage system considering both cycling and calendar aging expenses is made based on its usage of depth of discharge (DOD). In this study, the extensive simulation is conducted in MATLAB/Simulink platform, and it is found that SC is a better candidate than Li-ion battery in terms of economic assessment for hourly dispatching WEC power.

50 EE - Wind and Water Power Program - Water (EE-4↗
DOE OSTI2023

Corn stover‐derived porous carbon for asymmetric supercapacitors

In this investigation, hydrothermal liquefaction‐derived hydrochar from pulverized corn stover (avg. particle size 1.12 mm and ash content 6.75 wt%) is chemically activated with aqueous KOH in the presence of Pluronic F127 surfactant and thermally treated further up to 800°C to generate porous carbon (POC) with higher specific surface area and porosity. POC obtained under different processing conditions is thoroughly characterized by Brunauer‐Emmett‐Teller surface area analyzer, Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy. Metallic impurity present in POC is characterized by inductively coupled plasma mass spectrometry. Higher specific surface area POC is observed with the use of the surfactant during the activation process. Fully characterized POC is used with (Mn, Ti)‐mixed oxide electrode to fabricate asymmetric supercapacitor (ASC). Specific capacitance of ASC is measured by cyclic voltammetry (CV) technique using Gamry G‐300 potentiostat/galvanostat/ZRA. CV plots are obtained with different voltage scan rates whereas galvanostatic charge‐discharge plots are studied by varying the current density. Renewable corn stover‐derived POC prepared using Pluronic F127/KOH activation method is found to be highly suitable as an electrode material because of higher capacitance and electrochemical stability over 100 charging‐discharging cycles.

25 ENERGY STORAGE↗
DOE OSTI2026

Pseudocapacitive Titanium Oxynitride Nanowires for Ultrahigh Capacitance Supercapacitors

High-quality, multifunctional two-dimensional (2D) titanium oxynitide (TiNO) thin films and one-dimensional (1D) TiNO nanowires have been synthesized using a pulsed laser deposition, a simple, fast, and congruent evaporation method. First-principles calculations as a function of surface orientation and termination indicate that surface oxidation of TiNO nanowires can stabilize the (110) orientation observed experimentally. The specific capacitance value for the TiNO nanowire samples (2725 mF/cm 2 ) has been found to be nearly six times more than that of the TiNO thin film samples (400 mF/cm 2 ), which is attributed to the high packing density of TiNO nanowires over a given area. The nanowire samples have also been found to exhibit a significantly higher energy density (1.35 μWh/cm 2 ) than the TiNO thin-film samples (0.33 μWh/cm 2 ). Thus, the TiNO material system in thin-film and nanowire forms has been demonstrated to be a promising candidate for use as an electrode material in supercapacitors and other charge-storage applications.

capacitors↗
DOE OSTI2025

Confinement of Ti 3 C 2 T x MXene Nanosheets within a Polymer Matrix via In-situ Polymerization and Deposition on Carbon Cloth for Supercapacitors

Here, with the promising preliminary electrochemical performance, further investigation into polymer-filler interfacial regulation and confined ion transport in the CC/polymer/MXene system could provide deeper insights, paving the way for its application in flexible supercapacitors and other energy storage devices requiring highly adaptable electrodes.

36 MATERIALS SCIENCE↗
DOE OSTI2020

A Comparative Study of Imidazolium-Based Ionic Liquid-Single-Walled Carbon Nanotube Composites with Enhanced Conductivity Properties for Supercapacitor Applications

Mixtures of ionic liquids (ILs) containing single-walled carbon nanotubes (SWCNTs) were prepared and characterized to obtain electrolytes with optimized transport properties for use in energy storage devices such as supercapacitors. Imidazolium ILs bearing cations with side chains of different functionality coupled with bis(trifluoromethylsulfonyl)amide (NTf 2- ) or bis(fluorosulfonyl)-amide (FSA-) anions, were used in mixtures containing up to 5 wt% SWCNTs. At and above 2 wt% nanotube loading, the mixtures exhibited higher conductivities than the pure ILs, in spite of the extremely high viscosities. Loadings of 5 wt% produced very high conductivities, and studies of the temperature dependence indicated a change in the charge transport mechanism between 2 and 5 wt% loading. At 5 wt% loading, the highest conductivities (up to 540 mS/cm at 25 °C) were obtained for the ILs containing the NTf 2- anion. Overall, these results can significantly contribute to the development of improved energy storage devices.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Mechanistic Insights of Pore Contributions in Carbon Supercapacitors by Modified Step Potential Electrochemical Spectroscopy

Porous carbons are widely used as electrode materials for electrical double layer (EDL)-type supercapacitors. Differentiation of capacitance contributions from micropores and mesopores is important to understand porous carbon capacitive behavior. However, this remains challenging to accomplish. Here, we present an improved step potential electrochemical spectroscopy method to investigate the contributions to capacitance from hierarchical pores and redox processes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Neural Networks for Supercapacitor Modeling

This software implements a one-dimensional model of a supercapacitor and calibrates it to experimental data. A system of coupled partial differential equation models the salt concentration and the ionic and electronic potentials. The term in the equation modeling the capacitance contains a neural network, whose parameters are optimized to fit the provided experimental data. The software is written in python using the open-source library JAX to calculate the gradients needed for the optimization.

Salazar de Troya, Miquel↗