Charge Storage Capacity Research Articles

Structural, dielectric, thermoelectric, and magmatic properties of Er3+ ion substituted Mg-Zn spinal nanoferrites: High charge-storage capacitors and high-frequency microwave device applications

The Er-substituted magnesium and zink ferrite nanomaterials with the chemistry formula Mg0.8Zn0.2ErxFe2-xO4 (x = 0.00, 0.005, 0.01, 0.015, 0.02, 0.025) were generated in the study utilizing the citrate-gel auto combustion method. XRD is being used to investigate the cubic spinal structural structure. A transmission electron microscope (TEM) and a field emission scanning electron microscope (FESEM) were used to examine surface morphology. From the structural studies, the crystal sizes range from 14.46 to 96.40, with lattice parameters ranging from 8.434 to 8.449 and X-ray density (gm/cc) ranging from 4.585 to 4.671 and porosity (%) ranging from 7.67 to 7.91. The resulting macrostrain produces internal tension and can impair material grain growth. UV–visible absorption spectroscopy gives grain size pictures as well as quantifications at 300 K and 100 K, respectively. The wavelength range cut-off from 537.6 nm to 270.9 nm. The dielectric characteristics of the samples were tested at room temperature using an LCR meter at various frequencies. The dielectric parameters include the real component of the dielectric constant, the dielectric constant's imaginary portion, and the loss tangent. For each sample, the loss tangent of nanoferrites fell as the frequency increased. This type of material is used in capacitors and microwave devices. Thermoelectric power studies measured all samples. From the studies observed, the seeback coefficient decreases with increasing temperature and Er doping. The room temperature and low temperature magnetic properties were studied at 300 k and 100 k at low temperature ZFC and FC. The blocking temperature Tb was around 300 K.

Diverse Morphologies of Nb2O5 Nanomaterials: A Comparative Study for the Growth Optimization of Elongated Spiky Nb2O5 and Carbon Nanosphere Composite

AbstractControlled synthesis and design of nanomaterials with intricate morphologies and active phases offer new prospects in harnessing their unique chemical and physical properties for various applications. Herein, a facile and efficient hydrothermal approach is reported for obtaining various complex Nb2O5 nanostructures, including thin sheets, thick flakes, spiky and elongated spiky sea urchin morphologies using urotropin as a growth‐directing and hydrolyzing agent in various mixed and pure solvents. The detailed structural and chemical composition, surface morphology and crystallinity of as‐synthesized Nb2O5 nanostructures are presented. The urotropin concentration, reaction time, and water‐ethanol solvent mixture play a critical role for obtaining the elongated spiky sea urchin morphologies. The spiky Nb2O5 structures show a pseudohexagonal phase with less urotropin content, while thin sheets are obtained with a higher urotropin concentration and are primarily amorphous. These structures undergo transformation in their crystal phase and morphologies during calcination at higher temperatures revealing the active role of urotropin in stabilizing them. A composite of spiky sea urchin Nb2O5‐carbon nanospheres (suNb2O5‐CNS) is achieved by in‐situ growth of Nb2O5 in the presence of CNS without compromising on morphology, phase, and crystallinity. suNb2O5‐CNS composite is shown to possess higher charge storage capacity compared to its constituents for supercapacitor applications.

Nano graphene porous/conductive polymer as a composite material for energy storage in supercapacitors

AbstractThis research studies the improving effects of graphene porous (GP) on the supercapacitive performance of a polyaniline/graphene porous (PANI/GP) nanocomposite. GP nanosheets were synthesized via chemical vapor deposition, and PANI/GP was electrochemically composited through successive cyclic voltammetry. The samples were characterized by fast Fourier transform infrared (FTIR), x‐ray diffraction (XRD), and scanning electron microscopy (SEM), and energy‐dispersive x‐ray spectrometry (EDS) techniques. Porous GP nanosheets were uniformly dispersed in the composite structure. Furthermore, the electrochemical performances of the synthesized samples were compared using galvanostatic charge/discharge, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). Incorporating GP into the PANI significantly increased specific capacitance from 276 (in PANI) to 577 F/g (in PANI/GP). The electrochemical stability of electrodes was compared during 1000 successive charge/discharge cycles. After 1000 cycles, PANI/GP kept 90% of its initial capacitance, and only 25% of the charge storage capacitance of bare PANI remained.

A rGO/Cu0.7Fe0.3S2 composite electrode for asymmetric supercapacitor prepared via MIL-101 template strategy

As a branch of MOF, MIL has attracted much attention in the field of electrochemistry because of its high porosity and potential high charge storage capacity. Graphene oxide is considered as an ideal supercapacitor material because of its high electrical conductivity, high specific surface area and rich surface functional groups. The metal sulfides prepared with MIL as template not only inherit the structural characteristics of MIL, but also improve the electrical conductivity of the materials, which thus show excellent energy storage properties. In this work, the rGO/Cu0.76Fe0.24S2 composite was prepared through in-situ growth of MIL-101 on the surface of GO followed by copper nitrate etch, high temperature carbonization and hydrothermal sulfurization. To the best of our knowledge, it is the first time to report that rGO/Cu0.7Fe0.3S2 is used as the electrode of supercapacitor and tested for energy storage. The optimized rGO/Cu0.7Fe0.3S2 electrode exhibited good capacitive performances, including high specific capacitance of 661.2 F g−1 at 1 Ag−1 and remarkable cycle stability with 69 % after 5000 cycles. Employing the as-prepared rGO/Cu0.7Fe0.3S2 composites as positive electrode, the hybrid supercapacitor device displayed spectacular capacity of energy density (54.37 Wh kg−1), great power density (887.75 W kg−1) and impressive long-term stability of 70 % retention after 5000 cycles. The results show that the composite prepared with graphene oxide as substrate and MIL-101 (Fe) as template should be a promising materials for fabricating high-performance supercapacitor.

Iron oxide induced effects on the electrochemical stability and specific capacity of hafnium oxide electrode for supercapacitor applications

In the context of discovery of electroactive materials for energy storage applications with high energy storage, remarkable charge-discharge capabilities and outstanding electro-conductivity, herein, we have designed (hafnium oxide)x–(iron oxide)1−x based electrodes (where x = 1, 0.75, 0.50, 0.25, 0) in various stoichiometric ratios towards achieving a high-performance supercapacitor. The fabricated electrode successfully integrates the nanostructure design with synergistic effects, contributed by hafnium oxide and iron oxide nanoparticles. The morphological and structural aspects of this electrode have been systematically probed, followed by agile probing of electrochemical traits. Scientific techniques like cyclic voltammetry, galvanostatic charging/discharging and electrochemical impedance spectroscopy are the tools employed for the investigation of superior charge storage capacity. The nanocomposited electrode has achieved a superior specific capacitance of 1866 F g−1 at a current density of 1 A g−1 in 2 M NaOH electrolyte. Moreover, this electrode material has achieved an outstanding specific energy density of 64.79 Wh-kg−1 and specific power density of 249.8 W-kg−1 with a capacity retention of 79 % over 5000 cycles. This work significantly enhances the fundamental understanding of using high-k dielectrics in the field of energy storage devices.

Nano-casting synthesis of nanoporous carbons from biomass tar as sustainable electrode material for high-performance supercapacitor

Asphalt and coal tar, etc., as byproducts from fossil refinery featured with polycyclic carbon, are hot precursors for diverse advanced carbon functional materials. Herein, their bio-counterpart, namely biomass tar (BT), a notorious byproduct from biomass pyrolysis/gasification was successfully converted into O, N-co-doped carbon with interconnected porous structure via nano-casting with ZnO nano-rods. The optimal product obtained at 700 °C with mass ratio of 1:2:2 for biomass tar, nano-ZnO and KOH delivered specific capacitance up to 295F/g and 204F/g at current densities of 1 A/g and 20 A/g, respectively, and the specific capacitance was maintained at 86.3 % after 10,000 cycles of charging-discharging at 20 A/g. In the two-electrode system, a single electrode made of BTC-1Z-2K-700 still has a specific capacitance of 295.2 F/g at 0.2 A/g. Symmetrical supercapacitor device assembled with 1 M Na2SO4 as the electrolyte achieves the energy density of 27.19 Wh/kg at the power density of 640 W/kg. The impressive charge storage capacity and rating performance were attributed to its hierarchical porosity, large interface and low electric resistance. This work provides a novel out path for biomass tar valorization, as well as a sustainable and cost-effective candidate for electrode material for high-performance supercapacitor.

Covalently Functionalized Graphene Derivatives as Active Electrode Materials for Supercapacitors

Research efforts for supercapacitor electrode materials have become increasingly important due to the high demand for long-lasting, high-performing and environmentally friendly portable energy storage devices. Graphene-based materials and their hybrids have been shown to be very promising candidates for meeting these requirements. This short review summarizes recent advances in the development of graphene derivatives and focuses in particular on materials derived from graphite fluoride. Covalent graphene derivatives belong to a progressive class of highly efficient materials with tailorable structural and physicochemical properties that can be adapted to meet specific capacitive charge storage requirements, and, thus, enhance the most effective development of the energy storage field.

Lignin Functionalized with Catechol for Large‐Scale Organic Electrodes in Bio‐Based Batteries

Lignin, obtained as a waste product in huge quantities from the large‐scale cellulose processing industries, holds a great potential to be used as sustainable electrode material for large‐scale electroactive energy storage systems. The fixed number of redox‐active phenolic groups present within the lignin structure limits the electrochemical performance and the total energy storage capacity of the lignin‐based electrodes. Herein, the way to enhance the charge storage capacity of lignin by incorporating additional small catechol molecules into the lignin structure is demonstrated. The catechol derivatives are covalently attached to the lignin via aromatic electrophilic substitution reaction. The increased phenolic groups in all functionalized lignin derivatives notably increase the values of capacitance compared to pristine lignin. Further, solvent fractionation of lignin followed by functionalization using catechol boosts three times the charge capacity of lignin electrode.

MnO2 regulated potential window and storage capacity of CoxNi1-x(OH)2@MnO2 freestanding electrode for promoted membrane-less and decoupled water splitting

The realization of membrane-less and decoupled water splitting holds immense significance in facilitating cost-efficient and substantial H2 supply. In this study, a two-step hydrothermal reaction was employed to synthesize a CoxNi1-x(OH)2@MnO2 freestanding electrode, utilizing nickel foam (NF) as the substrate, MnO2 as the seed layer, and CoxNi1-x(OH)2 nanofiber as the surface layer. This fabrication approach resulted in a buffer electrode with an expanded potential window and enhanced charge storage capacity. Notably, the optimized CoxNi1-x(OH)2@MnO2@NF electrode functioned as an effective charge mediator, successfully decoupling the synchronous oxygen and hydrogen evolution reactions (OER and HER). Consequently, the need for separators was eliminated, introducing a novel two-step water electrolysis hydrogen production technology. Remarkably, the initial HER process at the cathode exhibited robust performance, sustaining a current of 100 mA for an impressive duration of 1500 s. Simultaneously, the CoxNi1-x(OH)2@MnO2 mediator underwent oxidation, attaining its corresponding oxidation state and yielding a commendable applied potential of 1.564 V. Subsequently, the OER step entailed the revival of the buffer electrode, enabling the facilitated production of anodic O2 at an operating potential of 0.392 V. Beyond that, the integration of an oxidizing buffer medium and a zinc foil enabled the development of a battery configuration, effectively replacing the second step of OER. This pioneering integration facilitated the concurrent realization of persistent H2 generation and battery discharging, presenting an innovative approach to hydrogen production that circumvents reliance on an external power supply. Thus, this decoupled HER-OER apparatus offers a propitious strategy for effectively converting renewable resources into hydrogen.

CoOx @NiMoN/Ti3 C2 Tx Interface for Stable High-Performance Electrochemical Energy Storage Devices.

Transition metal nitrides (TMNs) are promising electrode materials for use in high-performance electrochemical energy storage devices due to their unique properties, which include a high conductivity, pseudocapacitance, and energy density. However, structural instability during electrochemical reactions has limited their practical deployment for energy storage devices. In this context, the present study fabricated a CoOx @NiMoN/Ti3 C2 Tx electrode via in situ growth on Ni foam using hydrothermal treatment with post-nitrogenization. The effect of atomic layer deposition (ALD) of CoOx on the TMN/Ti3 C2 Tx interface and the consequent electrochemical charge storage mechanisms areinvestigated in detail. The proposed CoOx @NiMoN/Ti3 C2 Tx electrode delivers an impressive specific capacity in a 2m potassium hydroxide (KOH) electrolyte and isthen employed in both a hybrid solid-state supercapacitor (HSSC) with reduced graphene oxide and a symmetric SC in a 2m KOH + polyvinyl alcohol (PVA) gel electrolyte. Outstanding charge storage and high capacity retention during cyclic testing areobserved for both energy storage devices. The exceptional electrochemical performance of the fabricated electrode isa result of its high conductivity and high number of active sites. Here a feasible new strategy is demonstrated for the fabrication of stable energy storage devices with a high energy density using TMNs and MXenes.

2-D polypseudo-rotaxane network in (4Z,N'Z)-N’-(amino(pyridine-2-yl)methyl)isonicotionhydrazonic (apminh) Pb(II) complex: Synthesis, structural and quantum computational studies

The crystal structure of [Pb(apminh)Cl2] has been analyzed, revealing its potential as a useful component in a storage device. The complex crystallizes in the P1¯space group and is composed of a central Pb ion coordinated with two chloride anions and a tridentate apminh organic ligand. The ligand forms two chelating rings with Pb using oxygen and nitrogen atoms, resulting in a trigonal bipyramidal geometry of the central metal ion. The crystal packing of the complex is characterized by distinct intra and intermolecular interactions, with hydrogen bond interactions playing a crucial role. The complex forms 2D polymeric chains with intermolecular π...π stacking, which are bridged by the lattice solvent (methanol) through hydrogen bonds, making the 2D chains more stable. Quantum chemical calculations suggest that the complex has high kinetic stability, low chemical reactivity, electron-donating ability, and high charge storage capacity, making it a promising component for storage devices. The electronic structure analysis demonstrates the insulating nature, stable electronic structure, and long-lasting properties of the complex, providing insights into the chemical properties of the bonding in the complex. Overall, our results highlight the potential of [Pb(apminh)Cl2] as a storage device component, although further experimentation and testing are necessary to determine its suitability for this application.

Synergistic enhancement of dual-color electrochromic performance in NiO/CdS quantum dots composite film

NiO is an electrochromic material with extremely strong light modulation capability. However, the defects of the material, such as simple color change and poor cycle stability, limit its application in electrochromic devices and require further improvement and optimization. Nickel-based electrochromic films were firstly prepared by simple hydrothermal method and CdS quantum dots sensitization. The composite electrochromic films adsorbed CdS quantum dots show a multifunctional non-electrochromic film with multiple color changes. It shows up to 54.7% optical modulation range and reversible conversion of two colors. We believe that the electrochromic properties of the composite film are improved due to the synergistic effect of the combination of NiO and CdS in the composite film, which can improve the charge transfer dynamics and light modulation efficiency. Compared with NiO, CdS has a higher carrier density, which increases the charge storage capacity in the composite film, which can improve the color development efficiency and improve the electrochromic reaction. The existence of CdS in the composite film improves the structural stability of NiO. CdS acts as a buffer layer to reduce stress and prevent NiO degradation during repeated coloring and bleaching cycles, improving cycle stability and durability of electrochromic devices. This study provides a reference for the development of NiO polychromatic electrochromic materials and extends the range of non-electrochromic materials from metal oxides to sulfides.

Biochar facilitates biofuel production through batch single-stage and two-stage digestion of grass silage and cattle slurry

Grass silage and cattle slurry are the most abundant feedstocks for biogas in an Irish context. This work describes how to optimize their biomethane yield. Hydrolysis and biomethane yields from co-digestion of grass silage and slurry were enhanced in a biochar-supplemented two-stage digestion process. Biochar addition at the optimal dosage of 10 g/L in batch two-stage digesters led to the highest methane yield of 253 L per kilogram (kg) volatile solid (VS), which was 24% higher than that from two-stage digesters without biochar supplementation. For a batch single-stage digester, the biomethane yields were lower than the two-stage but 10 g/L biochar addition led to an increase to 218 L/kg VS as compared to 198 L/kg VS for the group without biochar supplementation. Volatile fatty acid accumulation increased with the enhancement of biomethane production in the biochar-supplemented two-stage reactors. The addition of biochar in single-stage and two-stage anaerobic digesters presented positive effects on the electrochemical properties of the digester contents, reflected by the increased charge storage capacity, reduced solution resistance and improved digester content conductivity. The methane yields in two-stage anaerobic digestion were shown to be strongly correlated (R2 = 0.92) with the concentration of extracellular polymeric substances. This evidenced that the interlaced conductive network established by extracellular polymeric substances and biochar was essential for direct interspecies electron transfer and biomethane production. This study demonstrated that biochar-supplemented two-stage anaerobic digestion is an optimal route for energy recovery from grass silage and cattle slurry.

High-performance MoSe2/rGO composites based on interface and phase engineering for all-solid-state symmetric supercapacitors

The energy storage capacity of supercapacitors depends on the electrode structure of the active material and its properties related to capacitance. Improving the properties of active materials through engineering strategies is essential to obtain high-energy supercapacitors. Here, we combine interface and phase engineering to overcome the inherent limitations of MoSe2 and improve their charge storage capacity. MoSe2 was anchored to reduced graphene oxide (rGO) using a simple hydrothermal method to form a heterogeneous structure. This approach provided a large number of electrode/electrolyte contact interfaces. The synergistic interaction of MoSe2 and rGO also enhances the overall electrical conductivity and structural stability. At the same time, the phase conversion of the MoSe2 material is triggered by the intercalation of Na+ ions to increasethe layer spacing and, thus, the charge storage capacity. In summary, MoSe2/rGO were prepared by engineering strategies with a high specific capacitance of 169.3 F g−1 at 0.5 A g−1. The assembled all-solid-state symmetrical supercapacitor (ASSC) devices have good cycling stability (83.1 % over 10,000 cycles) and potential practical applicability.

A comprehensive study of Bi2Sr2Co2Oy misfit layered oxide as a supercapacitor electrode material

Recently, the development of multiple functional energy storage materials having high energy storage capacity, expanded stability, and cost-effectiveness with eco-friendly nature is primary choice. Bi2Sr2Co2Oy (BSC-222) is misfit-layered oxide having significant thermoelectric (TE) capability with high temperature stability and eco-friendly characteristics. In present work, we successfully synthesized misfit layered BSC-222 oxide by using sol–gel method. X-ray diffraction, scanning electron microscopy, and atomic force microscopy are used to describe the structure and morphology of calcined BSC-222. Average thickness of prepared oxide sheets was found to be ∼30 to ∼40 nm. By using cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) in 3 M KOH, the electrochemical analysis of produced BSC-222 electrodes was carried out. The CV and GCD analysis showed that the BSC-222 oxide having high secondary cobaltite phases has better charge storage capacity (166.6C × g−1) at 2 mVs−1 and majorly charge is stored through diffusion-controlled charge storage mechanism. A chemical reactions schematic is proposed for the charge storage mechanism. Moreover, this calcined BSC-222 exhibits better cycling stability of 68.8 % up to 5000 GCD cycles at 1.5 Ag−1 current density. Hence, BSC-222 misfit layered oxide demonstrates that it has capability to store charge with its good TE ability. This present work provides the first step towards utilizing good TE misfit layered materials even after some doping or modulation in their structure to fabricate high energy density energy storage devices with multifunctional characteristics.

Boosting hierarchical construction and charge storage capacity of polyaniline arrays grown on the surface of carbon cloth with the aid of graphene interlayer

To satisfy the demands of high areal energy density for wearable devices, a strategy was presented to design hierarchical structured polyaniline (PANI) arrays on the surface of carbon cloth as the composite textile electrodes for lightweight and flexible supercapacitors. Benefiting from the introducing of graphene interlayer as conductive buffer layer and biomass organic acids including succinic acid, citric acid, malic acid, and tartaric acid as the dopants, the oriented growth of dense PANI array with hierarchical structure were greatly promoted especially in the presence of tartaric acid. Unique array structures constructed on the thin graphene layer significantly increase the specific surface area of the electrode, and facilitate the ion transport and dissipate stress from repeated polymeric volume change, resulting in considerably enhanced areal capacitance, rate retention and structural stability for PANI composite textile electrodes. The all–solid–state supercapacitor assembled with redox gel electrolyte possesses a high areal capacitance of up to 2181 mF cm−2 at the current density of 5 mA cm−2, and delivers a maximum energy density of 302.9 μWh cm−2 at the power density of 1752.1 μW cm−2 with excellent cycling stability and bending ability, thus demonstrating its great potential applications for wearable electronics.

Self-assembled electrochemically active biofilms doped with carbon nanotubes: Electron exchange efficiency and cytotoxicity evaluation

Thick electrochemically active biofilms (EABs) will lead to insufficient extracellular electron transfer (EET) rate because of the limitation of both substrate diffusion and electron exchange. Herein, carbon nanotubes (CNTs)-doped EABs are developed through self-assembly. The highly conductive biofilms (internal resistance of ∼211 Ω) are efficiently enriched at CNTs dosage of 1 g L−1, with the stable power output of 0.568 W m−2 over three months. The embedded CNTs can act as electron tunnel to accelerate the EET rate in thick biofilm. Self-charging/discharging experiments and Nernst-Monod model stimulation demonstrate a higher net charge storage capacity (0.15 C m−2) and more negative half-saturation potential (−0.401 V) for the hybrid biofilms than that of the control (0.09 C m−2, and −0.378 V). Enzyme activity tests and the observation of confocal laser scanning microscopy by live/dead staining show a nearly negligible cytotoxicity of CNTs, and non-targeted metabonomics analysis reveals fourteen differential metabolites that do not play key roles in microbial central metabolic pathways according to KEGG compound database. The abundance of typical exoelectrogens Geobacter sp. is 2-fold of the control, resulting in a better bioelectrocatalytic activity. These finding provide a possible approach to prolong electron exchange and power output by developing a hybrid EABs doped with conductive material.

Hydrophobicity Tuned Polymeric Redox Materials with Solution-Specific Electroactive Properties for Selective Electrochemical Metal Ion Recovery in Aqueous Environments.

Adaptable redox-active materials hold great potential for electrochemically mediated separation processes via targeted molecular recognition and reduced energy requirements. This work presents molecularly tunable vinylferrocene metallopolymers (P(VFc-co-X)) with modifiable operating potentials, charge storage capacities, capacity retentions, and analyte affinities in various electrolyte environments based on the hydrophobicity of X. The styrene (St) co-monomer impedes hydrophobic anions from ferrocene access, providing P(VFc-co-St) with specific response capabilities for and greatly improved cyclabilities in hydrophilic anions. This adjustable electrochemical stability enables preferential chromium and rhenium oxyanion separation from both hydrophobic and hydrophilic electrolytes that significantly surpasses capacitive removal by an order of magnitude, with a robust perrhenate uptake capacity of 329 mg/g VFc competitive with established metal-organic framework physisorbents and 17-fold selectivity over 20-fold excess nitrate. Pairing P(VFc-co-X) with other solution-specific electroactive macromolecules such as the pH-dependent poly(hydroquinone) (PHQ) and the cesium-selective nickel hexacyanoferrate (NiHCF) generates dual-functionalized electrosorption cells. P(VFc-co-X)//PHQ offers optimizable energetics based on X and pH for a substantial 4.6-fold reduction from 0.21 to 0.04 kWh/mol rhenium in acidic versus near-neutral media, and P(VFc-co-St)//NiHCF facilitates simultaneous extraction of rhenium, chromium, and cesium ions. Proof-of-concept reversible perrhenate separation in flow further highlights such frameworks as promising approaches for next-generation water purification technologies.

Improved dielectric properties of Sago Starch-Sodium Alginate (SS-SA) blend embedded with Cuc-Ags nanoparticles

Flexible polymer nanocomposites (NCs) based on Sago Starch-Sodium alginate (SS-SA) embedded Cu–Ag core-shell nanoparticles (Cuc-Ags NP) have been synthesized by solution casting approach. The structural and morphological properties of prepared NCs were investigated by X-ray diffraction (XRD), Transmission Electron Microscope (TEM), Field emission Scanning Electron Microscopy (FE-SEM), Atomic Force Microscopy (AFM) and Fourier Transform Infra-Red (FTIR) spectroscopy. The appearance of peaks in XRD spectra and lattice fringes in SAED pattern corresponding to Ag NP confirmed the core-shell architecture of Cuc-Ags NP, and the average crystallite size (calculated from XRD data) comes out to be 18.92 ± 0.16 nm. The interactions occurring between host matrix and NP have been confirmed using FTIR spectroscopy. The Cuc-Ags@SS-SA NC film exhibits superior tensile strength and Young's modulus as compared to pristine SS-SA film. The dielectric analysis revealed the highest dielectric constant for SS-SA matrix doped with 2.0 wt% Cuc-Ags NP (160.2 at RT) which is six times than that of pristine (at f = 50 Hz) and increases to 396.3 at 333 K. The Cole-Cole plots of Cuc-Ags@SS-SA NCs suggest the poly-dispersive nature of NC. The relaxation time (τ) decreases with increasing temperature and concentrations of Cuc-Ags NP in SS-SA. Such NCs with high ε′ and low ε" values have widespread applications as charge storage capacitors in flexible electronic devices.

Polyaniline/manganese nickel oxide/graphene composites as electrode materials for supercapacitors

AbstractThis study introduces a novel electrode material featuring a core‐shell intercalation structure. The material was synthesized using a simple and scalable method suitable for industrial replication. The outer layer of the electrode material comprises polyaniline, enveloping a nuclear structure composed of manganese dioxide and nickel oxide. This core‐shell configuration is then integrated into the lamellar structure of graphene oxide, resulting in the formation of PANI@(MnO2 + NiO)@GO composite. The combination of polyaniline, metal oxides, and graphene oxide demonstrates robust adsorption capacity, leading to the development of a three‐dimensional stable structure between the core and the shell. Additionally, graphene oxide contributes to the bilayer capacitance of the composites, resulting in simultaneous multiple synergistic effects and improved charge storage capacity. Electrochemical characterization reveals exceptional properties of this composite material, exhibiting a specific capacitance of 396 F g−1 at a current density of 0.5 A g−1 in a three‐electrode configuration. Furthermore, the material retains 82.6% of its capacitance after undergoing 3000 consecutive charge/discharge cycles. Calculations estimate the energy density and power density of this composite in a supercapacitor employing 1 M Na2SO4 electrolyte to be 43.2 W h kg−1 and 249.99 W kg−1, respectively.