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[Display omitted] • A combined theory–experiment rational design strategy is employed. • Multi-method calculations revealed transformation of molybdates during OER. • A hollow sandwich-like FeOOH/(NiCo)MoO 4 heterostructure was fabricated. • FeOOH/(Ni 1 Co 1)MoO 4 shows super alkaline OER, ƞ 10 = 225 mV, ƞ 200 = 318 mV, ƞ 1000 = 546 mV. • FeOOH/(Ni 1 Co 1)MoO 4 shows a specific capacity of 342 mA h g−1 at 1 A g−1. Structural engineering, including electronic and geometric modulations, is a good approach to improve the activity of electrocatalysts. Herein, we employed FeOOH and the second metal center Ni to modulate the electronic structure of CoMoO 4 and used a low temperature solvothermal route and a chemical etching method to prepare the special hollow hierarchical structure. Based on the prediction of multi-method calculations by density functional theory (DFT) and ab initial molecular dynamics (AIMD), a series of materials were fabricated. Among them, the optimal hollow FeOOH/(Ni 1 Co 1)MoO 4 by coating (NiCo)MoO 4 nanosheets on FeOOH nanotubes showed excellent performances toward high current density oxygen evolution reaction (OER) in alkaline and simulated seawater solutions, hybrid supercapacitor (HSC), and aqueous battery due to the well-controlled electronic and geometric structures. The optimal FeOOH/(Ni 1 Co 1)MoO 4 required overpotentials of 225 and 546 mV to deliver 10 and 1000 mA cm−2 current densities toward alkaline OER, and maintained a good stability for 100 h at 200 mA cm−2 with negligible attenuation. The FeOOH/(Ni 1 Co 1)MoO 4 //Pt/C electrolyzer exhibited a low cell voltage of 1.52 and 1.79 V to drive 10 and 200 mA cm−2 and retained a long-term durability nearly 100 h at 1.79 V. As the electrode of energy storage devices, it possessed a specific capacity of 342 mA h g−1 at 1 A g−1. HSC and SC-type battery devices were fabricated. The assembled HSC kept a capacitance retention of 94 % after 10,000 cycles. This work provided a way to fabricate effective and stable multifunctional materials for energy storage and conversion with the aid of multi-method calculations. [ABSTRACT FROM AUTHOR]

Energy storage technologies play a crucial role in addressing the intermittent characteristics of renewable energy sources, improving the stability of electrical grids, and decreasing the release of greenhouse gas emissions. In this study, we presented nickel indium oxalate (Ni 1-x In x C 2 O 4) as a promising material with potential applications in the field of electrochemical energy storage. The as-prepared Ni-In- oxalate sample was subjected to different physical characterizations, including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Regarding the electrochemical energy storage capability, the Ni 1-x In x C 2 O 4 electrode material exhibited a specific capacitance of 835 F g−1 (417.5 C g−1) at 1 A g−1. The incorporation of nickel (Ni) into the indium (In) oxalate nanoplates enhances their electrochemical performance. The presence of Ni in the nanoplates generated from substrate, improving the overall conductivity of the material and enhances its electrochemical reactions, thus leading to improved energy storage capabilities. [ABSTRACT FROM AUTHOR]

In the contemporary landscape of technological advancements, the burgeoning demand for portable electronics and flexible wearable devices has necessitated the development of energy storage systems with superior volumetric performance. Tungsten oxide (WO3), known for its high density and theoretical capacitance, is a promising electrode material for supercapacitors. However, low conductivity and poor cycling stability are still the key bottlenecks for its application. Herein, a novel composite comprising hollow porous WO3 spheres (HPWS) derived by template method was electrostatic self-assembled on the surface of the Ti3C2T x nanosheets. The resulting electrodes exhibited ultra-high volumetric capacitance of 1930 F cm−3 at 1 A g−1 and rate capability of 46% at 50 A g−1, attributed to enhanced ion accessibility from microporous structure and electron transport from conductive network of Ti3C2T x even at a high packing density of 3.86 g cm−3. Utilizing HPWS/Ti3C2T x as the negative electrode and porous carbon as the positive electrode, the assembled asymmetric supercapacitor achieved an energy density of 31 Wh kg−1 at a power density of 650 W kg−1 with over 107% capacitance retention after 5000 cycles. This work provides a promising approach for developing next-generation supercapacitors with ultra-high volumetric capacitance. [ABSTRACT FROM AUTHOR]

Polyvinyl alcohol/lithium chloride hydrogel (PVA/LiCl) is one of the most used electrolyte in supercapacitors. Increasing the ionic conductivity and operating temperature range of PVA/LiCl would greatly boost the electrochemical performance of supercapacitors and enhance the devices’ environmental adaptability. This is of great significance yet rarely concerned about in energy communities. In this work, SiO2 functionalized PVA/LiCl (PVA‐SiO2/LiCl) is experimentally realized with high ionic conductivity and wide operating temperature range. The spectroscopic and theoretical experiments prove that SiO2 significantly regulates cation solvation structure to promote cation‐anion pair dissociation and diminish coagulation of PVA chains, increasing ionic conductivity from 19.01 mS cm−1 of PVA/LiCl to 56.17 mS cm−1 of the new electrolyte. SiO2 can also prevent cation‐anion association as temperature decreases, and the abundant hydroxyl groups on the SiO2 and the stretched PVA chains tune hydrogen bonds among dipolar water molecules. They effectively expand the operating temperature range of PVA‐SiO2/LiCl. PVA‐SiO2/LiCl greatly boosts the electrochemical performance of MnO2‐based supercapacitor. The design concept developed here opens up a way toward high‐performance hydrogel electrolyte development. [ABSTRACT FROM AUTHOR]

In order to fully utilize industrial lignin, a comparative study was conducted on the properties of porous carbon electrodes prepared by activating different industrial lignin as precursors. The results revealed that carbon electrodes prepared with sodium lignosulfonate (CM-S) exhibited superior specific surface area (SSA) (1,593.5 m2 g−1) and pore volume (PV) (1.03 cm3 g−1) due to the largest relative molecular mass (Mn = 4,539, Mw = 7,290), which is greater than that prepared with alkali lignin (CM-A) and kraft lignin (CM-K), and displayed a well-developed micro-mesoporous macropore hierarchy which was feasible for the efficiency of electron mobility. The electrochemical properties of materials were evaluated, and CM-S showed a mass-specific capacitance of 201 F g−1 at 0.2 A g−1 current density, along with an impressive capacitance retention rate of 54.7 % at 10 A g−1 current density, which is more potential than CM-A and CM-K (specific capacitances: 100 F g−1 and 75 F g−1 respectively). Additionally, maximum energy and power density of CM-S were measured to be 6.98 W h kg−1 and 2306 W kg−1 with excellent retention rate of 95.5 % after 10,000 charge–discharge cycles at a current density of 5 A g−1. Comparatively, sodium lignosulfonate, compared with alkali lignin and kraft lignin, emerges as a more ideal precursor material for porous carbon electrode. [ABSTRACT FROM AUTHOR]

In this paper, a high‐gain bidirectional DC–DC converter is presented for electric vehicles where low terminal voltage source like a supercapacitor is used along with the battery. The supercapacitor provides or absorbs large amount power during acceleration and deacceleration and extends the life of main energy source, that is, battery. The supercapacitor terminal voltage varies considerably during charging and discharging activities; hence, a bidirectional DC–DC converter with a high‐voltage conversion ratio must be used to connect the lower supercapacitor voltage to the higher DC‐link voltage. Such application requires steep voltage conversion ratio along with continuous gain‐based bidirectional DC–DC converters. In this study, a typical CuK converter is employed to produce a voltage gain of 3X and X/3 with the ability to transmit power in both directions. The suggested bidirectional converter has a continuous current on both the low‐ and high‐voltage sides, which reduces the requirement for filter capacitance and increases the lifespan of the supercapacitor and DC‐link capacitor. Further, inherent inrush current safety is provided by the proposed converter as the inclusion of an inductor in the path of capacitor charging or discharging. Both in the charging and discharging phases, a detailed steady‐state analysis of the proposed circuit was performed. Moreover, a deep discharge analysis of the supercapacitor and its implication on the performance of the converter is also investigated. [ABSTRACT FROM AUTHOR]

Global energy crisis imposes immense obstacles leading towards development of innovative devices, and supercapacitors (SCs) are thought to be a viable energy storage technology. The engineering of nanostructured materials with a distinct and consistent morphological design is seen as a better option for various range of electrochemical energy sources. This study reports novel binder-free Ni 3 S 2 /CoS 2 electrode material that acquires higher energy, higher energy density, as well as its simple preparation method, low cost, and earth–abundant resources. The morphological, structural, and textural characteristics resulted in surface area of 46 m2 g−1 of Ni 3 S 2 /CoS 2 that will increase active sites also. The synthesized nanocomposite has particle size of 41.1 nm that leads to enhanced active sites and greater surface area as confirmed through BET analysis. Ni 3 S 2 /CoS 2 nanocomposite has high specific capacity around 828.14 F g−1 at 5 mV s−1 sweep rate using 2 M KOH, a high energy density around 115.01 Wh kg−1, and power density of 1000 Wh kg−1. Ni 3 S 2 /CoS 2 acquires higher ionic conductivity of 5 S m−1, this will enhance the inter-layer transference of electrons, and these results perfectly correlates with EIS, resulting in charge transfer resistance value of 0.9 Ω for nano-composite. These enhanced electrochemical capabilities of Ni 3 S 2 /CoS 2 hold significant potential in practical viability. [ABSTRACT FROM AUTHOR]

Present work reports on the synthesis of NiO-incorporated nanotorous ZrO2 synthesized by facile co-precipitation method for supercapacitor application. The as-synthesized composite was characterised using FTIR and XRD confirming the successful synthesis of ZrO2-NiO composite (ZNC). FESEM analysis also revealed morphology transition from nanoclusters of tiny ZrO2 particles and stacked flakes of NiO to self-assembled nanotorus ZNC. Electrochemical analyses (like CV, GCD, EIS) also revealed improved electrochemical behaviour of ZrO2 whose specific capacitance increased from 87.77 F/g to 251 F/g in ZNC at 1 A/g. This could be attributed to the synergistic effect of nanotorous morphology in the presence of NiO. These observations were well complemented by a reduced band gap (~ 2.96 eV) and lower charge transfer and solution resistance. A mechanistic insight was also proposed for a deeper understanding of the development of torous structured material. This work provides a closer look into how NiO-driven torous morphology of ZrO2-NiO composite has improved the electrochemical performance of ZrO2. [ABSTRACT FROM AUTHOR]

The green energy storage of polyaniline, without major wastages excreted into the environment is effectively demonstrated by using the polyaniline as supercapacitor electrode and the by-product obtained during the synthesis of polyaniline as its electrolyte. This green approach to the energy storage properties of sulphuric acid doped polyaniline (H-PANI) exhibited a substantial improvement in its energy storage, compared to the conventional approach of using an ionically conducting liquid as electrolyte like 1 M H2SO4 (SA), separately. The amelioration of 40.44% was achieved when the by-product obtained as supernatant liquid (SL) was used as electrolyte compared to SA. The H-PANI provided a specific capacity (Q) of 146.4 C g−1, a specific energy (E) of 24.40 W h kg−1 and a specific power (P) of 1.200 kW kg−1 at 1 A g−1 in the presence of SA. The Q of 205.6 C g−1, E of 34.26 W h kg−1 (similar range of E of Pb-acid batteries), P of 1.200 kW kg−1 were achieved in the presence of SL at 1 A g−1 and a high rate capability of 29.18% retention of initial Q up to 25 A g−1 was also achieved. This approach is useful to harvest high energy characters from PANI. [ABSTRACT FROM AUTHOR]

The development of industries has caused severe impacts on the environment and increased the demand of using energy. In this work, reduced graphene oxide-doped water hyacinth carbon aerogels (rGO/WHCA) were synthesized by cross-linking cellulose with poly(vinyl alcohol) as a binder and addition of graphene oxide (GO) as rGO precursors, followed by freeze-drying and pyrolysis techniques. The obtained materials were studied for adsorption of methylene blue (MB) in water and applied as electrodes for the supercapacitor. The impact of GO content on the characteristics, adsorption performance, and electrochemical properties of the rGO/WHCA were investigated. Besides, the concurrent effects of the adsorption time, and MB concentration on the adsorption capacity were evaluated via the response surface methodology according to the Box–Behnken model. The obtained rGO/WHCA materials exhibited ultralow density, high porosity, and an abundance of meso- and micropores structures. Especially, rGO/WHCA materials showed a great ability for removing MB in water with the highest adsorption capacity up to 95.03 mg/g after 420 min with the initial MB concentration of 150 ppm at pH 9 and performed the electrical double-layer capacitors (EDLCs) in a three-electrode system with an outstanding specific capacitance of 272.08 F/g at current density of 0.5 A/g. The obtained results open a potential pathway of using biomass sources, like water hyacinth, for solving environmental issues and the demand for energy storage. [ABSTRACT FROM AUTHOR]

In order to effectively develop and utilize new energy, people urgently need high-performance super- capacitors to provide energy storage and conversion. Electric double layer structure plays a key role in supercapacitors. In this work, the molecular dynamics simulation was taken to an open graphene nanochannel (1-2 nm), and the double-layers structure of KCl solution inside the nanochannel was studied. Meanwhile, the similarities and differences of the double-layer structure under fixed charge simulation (Q) and constant potential simulation (U) were compared. The results show that the mirror image effect of the conducting graphene wall is considered in the constant potential simulation method, which makes the results more consistent with the practical materials. The mirror image effect can absorb extra ions. Thus it enhances the concentration of anion and cation in the pore, which may contribute to the improvement of electrode capacitance. Through the study of different channel heights, it is found that water molecules play a decisive role as dielectric materials in water-based supercapacitor. It can largely offset the change of electric double layer under different ions and different channel heights, resulting in a similar capacitance under different conditions. [ABSTRACT FROM AUTHOR]

This work reports a green synthesis of CuO/NiO nanocomposite with different CuO/NiO ratios. The X-ray diffraction (XRD) confirmed the existence of both CuO and NiO. This was also confirmed by energy dispersive X-ray (EDX). Scanning electron microscopy (SEM) reveals that changing the compositions of the nanocomposites resulted in different surface morphologies with different particle shapes, sizes, and levels of aggregation. Nitrogen adsorption-desorption analysis showed microporous structures with pore size in the range of 1.66-1.75 nm and surface area in the range of 82-513 m2g−1. The supercapacitive activity was examined by cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD). The results display that the 1C3N exhibited the highest capacitive performance of 1072 Fg−1 compared to 760, 716, and 260 Fg−1 for 3C1N, 4 N, and 4 C, respectively. Furthermore, the 1C3N electrode shows a cyclic stability of 72% after 4000 cycles, which makes it a promising candidate for supercapacitive applications. [ABSTRACT FROM AUTHOR]

Ammonium ions (NH4+) being the non-metallic charge carriers are deemed safe while enhancing the charge storage performance. To enable long term efficiency in energy storage systems, one needs to overcome the primary obstacle to ammonium storage, which is to develop materials with layered structures having enough interlayer separations as electrodes for hosting NH4+ ions reversibly. To address the issues, herein, synthesis of a molybdenum oxide–sulfide composite with titanium oxide atomic layering was prepared to serve as active negative electrode (negatrode). The growth of MoS2 nanosheet on hydrothermally grown MoO3 nanosheets was confirmed from the low- and high-resolution imaging. The presence of uniform layer of TiO2 over MoS2/MoO3 electrode was verified through imaging and compositional analysis. Thanks to its distinct nano-architecture and surface atomic layering, the constructed TiO2/MoS2/MoO3 electrode was able to deliver specific capacitance of 624 F/g at a current density of 3 A/g. After 3000 charge–discharge cycles, the electrode's retention was close to 86% at 5 A/g current density. The present results provide insights into the development of non-metal ion-electrolyte-based energy storage systems. [ABSTRACT FROM AUTHOR]

To cater the ever growing energy demand and durability for modern applications like portable electronic gadgets, hybrid electric vehicles, etc., enormous research has been done to develop high capacity electrochemical energy storage devices. Among different allotropes of carbon, graphene, is emerged as an excellent candidate for energy conversion and storage applications because of its unique properties, including high specific surface area (2630 m2/g), good chemical stability and excellent electrical conductivity. To obtain high specific capacitance as well as high rate capability, the use of MnO2 based composite materials is predicted as potential candidate. Strategies to modify supercapacitor performance of MnO2 based composites are reported by various research groups. Polyaniline is one of the most studied conducting polymer due to good conductivity, environmental stability, low weight, easy synthesis on large scale and economic importance for industrial applications. In commercial supercapacitors, activated carbon is commonly used as electrode materials. Low energy density of carbon materials cannot be efficient for their effective use in energy storage applications. Thus, preparation of supercapacitors by using hybrid material with incorporation of metal oxides and conducting polymers in graphene can provide exceptional energy as well as power density. Nanocomposite materials have attracted much attention due to the synergetic effects between the components which shows better electrical properties. Further, the improvement in the electrical properties in hybrid materials is attributed to the direct interfacial interaction. In this study, specific capacitance of Polyaniline/MnO2/Graphene/Graphene oxide composite material was found to be 1882.32 (Fg−1) with symmetric galvanostatic charge/discharge curves and 97.61% capacitance retention after 6063 cycles in cycle performance. [ABSTRACT FROM AUTHOR]

Electrochromic supercapacitors, which indicate energy states through optical color changes, are gaining significant attention for their potential in energy saving and recycling. In this study, a novel metal–organic coordination polymer (DTPB‐MCP) is successfully synthesized using an N,N’‐diphenyl‐1,4‐phenylenediamine (DTPB)‐functionalized phenanthroline ligand. The resulting DTPB‐MCP film demonstrated desirable electrochromic performance in both the visible light (ΔT:77.6% at 730 nm) and near‐infrared (ΔT: 49.2% at 1410 nm) regions, as well as decent energy‐storage capabilities (16.4 mF cm−2 at 0.1 mA cm−2), attributed to the presence of multiple redox centers. Furthermore, a hybrid electrochromic supercapacitor is also developed by combining DTPB‐MCP with V₂O₅ (DTPB‐MCP//V₂O₅), showcasing a significant optical contrast (47.6% at 750 nm and 14.5% at 1420 nm), an acceptable capacitance of 11.5 mF cm−2 with good rate performance, and impressive cycling stability (maintaining 81% of capacitance after 2750 charging/discharging cycles). In addition, >60% of electric energy can be reused to drive small household appliances during the bleaching process. The design principles outlined in this study offer valuable insights into the development of high‐performance dual‐band electrochromic energy‐storage materials, highlighting their potential applications in energy recovery and reuse. [ABSTRACT FROM AUTHOR]

ABSTRACT The redox active organometallic compounds are the prominent supercapacitor electrode materials due to the attractive properties like stable redox scheme, good electron transfer mediator, and low oxidation potential. The key advantage of the organometallic compounds is that the electronic property of the electrode can be modified by altering and functionalizing the ligands around the metal atom. In this work, we synthesized cobalt‐oxyquinolinate (Co‐Q) organometallic compound by solvothermal method. To improve the electrical conductivity, the reduced graphene oxide (RGO) is grafted on Co‐Q. The electrochemical behaviour of Co‐Q is improved by the addition of RGO. The specific capacitance of Co‐Q layered on RGO is greater (1206 mF cm−2) than Co‐Q (670 mF cm−2) at current density of 1 mA cm−2. This is due to the increase in active sites after the incorporation of RGO on Co‐Q; further, this promotes the diffusion process. The fundamental electrochemical analyses, including cyclic voltammetry, galvanostatic charge–discharge analysis, and electrochemical impedance analysis, provided the information about the electrochemical energy storage performance. Dunn's method is used to understand the diffusion and capacitive contributions of the electrode material during energy storage. From the electrochemical analysis, Co‐Q layered on RGO is a suitable material for the energy storage application due to its high diffusion and stability. [ABSTRACT FROM AUTHOR]

The increasing need for electrode materials exhibiting improved performance to meet the requirements of supercapacitors is on the rise. Hybrid electrodes, which combine reduced graphene oxide (rGO) with transition metal-based oxides, have emerged as promising materials due to their impressive specific capacitance and cost-effectiveness, attributed to their synergistic properties. In the present study, a binder-free CoOrGO composite electrode was synthesized using a facile, fast, and simple one-step co-precipitation method. This was done to improve both capacity and stability for supercapacitor applications. The composite materials underwent comprehensive characterization utilizing various surface analytical techniques, including X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), field-emission scanning electron microscopy (FE-SEM), fourier-transform infrared spectroscopy (FTIR), and Brunauer–Emmett–Teller (BET) analysis. Electrochemical measurements of the CoOrGO composite revealed at current density of 2 A cm− 2 a specific capacitance of 132.3 mF cm− 2, with an impressive 95.91% retention of capacitance after 7000 cycles. The results from electrochemical impedance spectroscopy (EIS) highlighted a meager low relaxation time constant of 0.53 s for the composite films. The reason behind this can be linked to the synergistic interactions, and minimal charge transfer resistance exhibited by the porous electrode without binders. Based on the obtained results, this work introduces a flexible methodology for crafting advanced energy storage systems. This demonstrates the potential for designing high-efficiency supercapacitors that are suitable for a broad range of large-scale applications. [ABSTRACT FROM AUTHOR]

ABSTRACT Organic dyes are a substantial contribution to environmental pollution and are considered as hazardous. These compounds are widely used in various industries like textiles, food, paper, cosmetics, and printing. A cationic dye, such as Fast Blue (FB) and Congo Red (CR), is an example of organic compound with several commercial uses but dangerous for environment and human beings. Copper Magnesium Vanadate NPs (CuMgV NPs) were successfully prepared using the combustion method in which Neem extract was used as a fuel. The XRD, FTIR, and FESEM techniques were used to analyze the sample's structure and morphology. The XRD reveals monoclinic structure of the CuMgV NPs with average particle size around 30 nm. The presence of tiny particles that prefabricated to form a widely distributed, spherical shape, and size between 15 and 25 nm was observed by HRTEM microscopic investigations. The CuMgV NPs were assessed using several electrochemical techniques. In photocatalytic tests, 120 min of UV light irradiation was sufficient to achieve a 58% and 55.52% decolorization rate for the industrial pollutants CR and Fast FB dyes. CuMgV NPs were found to have a specific capacitance value of 560.5 Fg−1 at 1 Ag−1 and a retention rate of 89% after 4000 cycles. These features promote the production of NPs for energy and environmental applications and provide greater insight into the characteristics of the material. [ABSTRACT FROM AUTHOR]

Creating the porous Zinc-Zeolitic Imidazolate Framework (Zn-ZIF) using a solvothermal technique addresses the need for advanced materials with distinctive properties and cost-effectiveness in modern applications. The PXRD, SEM, UV-DRS, TEM, and TGA/DTG are used to characterize different concentrations of Zn-ZIF. Zn-ZIF's crystalline structure and phase purity have been verified by PXRD. Using diffuse reflectance spectra, the Kubelka-Monk function determined the band gaps of the Zn-ZIF samples, and scanning electron microscopy revealed a more porous structure. At 77 K and 1 bar, the Zn-ZIF solution with a 2:1 ratio had the highest hydrogen storage capacity (1.71 wt%). The electrochemical behavior of several Zn-ZIF electrodes in a 6 M KOH electrolyte was evaluated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) experiments. The Zn-ZIF electrode with a 2:1 ratio exhibits a low charge transfer resistance and a high proton diffusion coefficient (D) of 1.687 × 10−4 cm2 s−1. The characteristics of the 2:1 synthesized Zn-ZIF electrode as a supercapacitor were investigated. Our analysis of the generated Zn-ZIF material's specific capacitance values after 2000 cycles revealed an impressive retention rate of nearly 89 %, with values of 296.6 Fg-1. In addition, we examined the photocatalytic activities of the as-synthesized material by exposing it to ultraviolet light and seeing how it degraded organic dyes such as Cango-Red (CR) dye. With a photocatalytic efficacy of 95.06 % for CR dye, Zn-ZIF (2:1 ratio) is the most effective. These findings should provide new knowledge for researchers interested in developing novel Zn-ZIF materials for photocatalytic, energy storage, and hydrogen storage applications. [ABSTRACT FROM AUTHOR]

In order to develop advanced energy storage devices, it is necessary to manufacture supercapacitor electrode that have both long electrochemical cycle lifetimes and high energy densities. These properties can only be obtained by developing heterostructure pseudo-capacitive materials. The combination of MnO 2 nanorods and ZnCr 2 O 4 nanoparticles resulted in a synergistic effect, which increased the electroactive surface area for charge storage. This effect was not observed when each component utilized individually. The material ZnCr 2 O 4 nanoparticles facilitated the MnO 2 nanorods. In present study, ZnCr 2 O 4 , MnO 2 and their composite was fabricated by simple sonication process. These fabricated samples were tested by using different techniques which includes X-ray diffraction (XRD), Raman analysis, Brunauer Emmett Teller (BET) and scanning electron microscopy (SEM). Electrochemical analysis of fabricated materials exhibited an exceptional specific capacitance (C sp = 1175.35 F g−1), energy density (E d = 15.95 Wh Kg−1) and power density (P d = 869.4 W kg−1). These materials are anticipated to act as the support for electrochemical energy storage devices that utilize an ideal electrode structure, meticulously select the appropriate transition metal oxide (TMO) and analyse electrochemical characteristics for supercapacitive performance. This study exhibits the remarkable efficiency of the nanostructured ZnCr 2 O 4 /MnO 2 electrode in supercapacitors with high energy density (E d). [ABSTRACT FROM AUTHOR]

MXene is a novel two-dimensional layered nanomaterial with a very large specific surface area and abundant surface functional groups, endowing it with unique physical and chemical properties. MXene can be compounded with other functional materials to significantly improve the performance of MXene composites or broaden their application scope. Meanwhile, with the development of flexible composite preparation technology, it has promoted the continuous expansion of its application fields. The introduction and combination of different materials can improve the performance of flexible composites and make them have a broader application prospect. In recent years, researchers have started preparing MXene materials as flexible composites for applications such as supercapacitors, sensors, electromagnetic shielding and thermal management. This paper gives a brief introduction to flexible composites and MXene materials, reviews the applications of MXene based flexible composites in various fields as well as the research progress, and provides an outlook on their future development direction. [ABSTRACT FROM AUTHOR]

Tea waste contains various substances with phenolic hydroxyl groups, including lignin, tannins, tea polyphenols, etc., which are rarely utilized. In this study, tea waste was directly dispersed with graphene oxide to prepare tea waste/reduced graphene oxide (TW/rGO) hydrogel through a one-step hydrothermal method. The prepared hydrogel presented a continuous three-dimensional porous structure and exhibited good mechanical properties with a compressive strength of 53.4 ± 4.0 kPa. It also showed excellent electrochemical performance as an electrode material. Its specific capacitance reached 434.7 F g−1 at a current density of 1 A g−1, and its capacitance retention was 55.8% when the current density was increased to 100 A g−1. In addition, an TW/rGO assembled all-solid-state supercapacitor demonstrated a superior specific capacitance of 372.8 F g−1 and a competitive energy density of 12.9 Wh kg−1 at 1 A g−1. [ABSTRACT FROM AUTHOR]

Because of safety concerns associated with the use of liquid electrolytes and electrolyte solutions, options for non-liquid materials like gels and polymers to be used as ion-conducting electrolytes have been explored intensely, and they attract steadily growing interest from researchers. The low ionic conductivity of most hard and soft solid materials was initially too low for practical applications in supercapacitors, which require low internal resistance of a device and, consequently, highly conducting materials. Even if an additional separator may not be needed when the solid electrolyte already ensures reliable separation of the electrodes, the electrolytes prepared as films or membranes as thin as practically acceptable, resistance may still be too high even today. Recent developments with gel electrolytes sometimes approach or even surpass liquid electrolyte solutions, in terms of effective conductance. This includes materials based on biopolymers, renewable raw materials, materials with biodegradability, and better environmental compatibility. In addition, numerous approaches to improving the electrolyte/electrode interaction have yielded improvements in effective internal device resistance. Reported studies are reviewed, material combinations are sorted out, and trends are identified. [ABSTRACT FROM AUTHOR]

MXenes possess high metallic conductivity and excellent dispersion quality and pseudocapcitance. Their good hydrophilicity makes them particularly suitable as eco-friendly inks for printing applications. However, MXenes are prone to oxidization in aqueous dispersions, and it is very important to improve their stability. Here, the long-term storage of MXene aqueous dispersions was realized by the introduction of sodium L-ascorbate (NaAsc) as the antioxidant. The preserved MXenes exhibited very stable electrochemical properties. Even after 60-day storage, the supercapacitor with preserved MXenes as the electrode still demonstrated an excellent specific capacitance of 381.1 F/g at a scan rate of 5 mV/s and a good retention rate of 92.6% after 10,000 consecutive cyclic voltammetry measurements, which was nearly the same as that of fresh MXenes. The results indicate a facile and efficient method to realize the long-term storage of MXene aqueous dispersions for mass use in future energy storage. [ABSTRACT FROM AUTHOR]

In this study, we synthesized and characterized Nd and Co modified bismuth ferrite nanoparticles (BNFCO) using mechanical milling. X-ray diffraction (XRD) analysis has provided confirmation of the distorted rhombohedral, mixed rhombohedral-tetragonal and tetragonal perovskite structure with space group R 3 c and P2mm. Notably, these nanoparticles exhibited a high dielectric constant and low loss values at low frequencies and high temperatures, remaining around 103 up to 373 K before increasing to approximately 104, which opens new avenues for exploring temperature-sensitive dielectric properties. The AC conductivity adhered to Jonscher's power law, with dc conductivity values ranging from 10−5 to 10−3 s/cm, representing a significant advance in understanding electrical conduction in nanomaterials. Furthermore, we assessed the electrochemical behavior of the fabricated samples at varying concentrations using cyclic voltammetry, Galvanostatic charge and discharging (GCD), and electrochemical impedance spectroscopy (EIS) on a modified electrode. BNFCO (0.20) displayed exceptional properties with a capacitance of 510 F g−1 and a capacitance retention of 93.9 % after 5k cycles, making BNFCO nanomaterials potential candidates for supercapacitor applications. The multifunctional properties of Nd and Co modified bismuth ferrite nanoparticles presented in this study offer unparalleled opportunities for transformative applications in supercapacitors and optoelectronic devices. [ABSTRACT FROM AUTHOR]

[Display omitted] The development of novel materials for electrodes with high energy densities is essential to the advancement of energy storage technologies. In this study, N -doped layered porous carbon with ZIF-67-derived binary CoFe 2 O 4 -Fe particles was successfully fabricated by the pyrolysis of an Fe-based chitosan (CS) hydrogel mixed with ZIF-67 particles. Various characterization techniques were employed to assess the performance of the prepared porous CoFe 2 O 4 -Fe@NC composite. This composite exhibits excellent performance owing to the effective combination of multivalent CoFe 2 O 4 -Fe particles derived from ZIF-67 with N -doped porous carbon substances with a high surface area, which helps to accelerate ion and charge transfer. The specific capacitance of the CoFe 2 O 4 -Fe@NC composite carbonized at 700 °C reached 3960.9F/g at 1 A/g. When this composite is combined with activated carbon (AC) to construct an asymmetric supercapacitor (ASC), a density of energy of up to 84.9 W h kg−1 is attained at a power capacity of 291.6 W kg−1. Moreover, this composite maintained a capacitance retention of up to 94.9 % after 10,000 cycles. This work offers new perspectives on high-performance supercapacitors and their applications. [ABSTRACT FROM AUTHOR]

Schematic illustration of the fabrication processes of NYCs samples under different pyrolysis temperature. [Display omitted] The energy storage capacity of porous carbon materials is closely tied to their surface structure and chemical properties. However, developing an innovative and straightforward approach to synthesize yolk-shell carbon spheres (YCs) remains a great challenge till date. Herein, we prepared a series of porous nitrogen-doped yolk-shell carbon spheres (NYCs) via a "pyrolysis-capture" method. This method involves coating the resorcinol–formaldehyde (RF) resin sphere with a layer of compact silica shell induced by 2-methylimidazole (ME) catalysis to produce a confined nano-space. Based on the confined effect of compact silica shell, volatile gases emitted from the RF resin and ME during pyrolysis can not only diffuse into the pores of the RF resin but can also be captured to form an outer carbon shell. This results in the tunable structures of NYCs materials. As the pyrolysis temperature rises, the shell thickness of NYCs reduces, the pore size expands, the roughness increases, and the N/O content of surface elements is enhanced. Notably, as an electrode material used for supercapacitors, the optimized NYCs-800 exhibits excellent performance with a capacitance of 301.2F g−1 at the current density of 1 A/g and outstanding cycling life stability of 96.1% after 10,000 cycles. These results signify that controlling the surface structure and chemical properties of NYCs materials is an effective approach for constructing advanced energy storage materials. [ABSTRACT FROM AUTHOR]

In this study, activated carbon (PPAC) is produced from pomegranate peel waste by activation of sodium hydroxide (NaOH) in the first stage. In the second stage, ammonia activation for nitrogen doping is carried out on PPAC (N-doped PPAC). In the third stage, zinc oxide (ZnO) doping is carried out on the obtained N-doped PPAC sample (ZnO@N-doped PPAC). The surface properties of the produced composite are examined by scanning electrode microscope (SEM), X-ray diffraction analysis (XRD), Energy dispersive X-ray (EDX), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy(XPS), micro Raman and nitrogen adsorption analyses. The electrochemical performance of the supercapacitor is investigated by cyclic voltammetry (CV), charge-discharge curves(GCD), and electrochemical impedance spectroscopy (EIS). N-doped PPAC and ZnO@N-doped PPAC composite materials are used as supercapacitor electrodes. Specific capacitance values of 207.4 and 265.2 F/g in 1 M sulfuric acid(H 2 SO 4) are obtained with N-doped PPAC and ZnO@N-doped PPAC electrodes, respectively. Additionally, cycle stability is achieved with a capacitance retention of approximately 86% after 5000 cycles at 0.6 A/g. The maximum energy density and power density of ZnO@N doped PPAC were calculated as 7.29 Wh/kg and 3600 Wh/kg, respectively. [Display omitted] • Ammonia and ZnO incorporated into PPAC based on biomass waste were performed. • There is an increase in the capacitance value of 28% by ZnO doping on N-doped PPAC. • Specific capacitance of 265.2 F/g at 1 A/g for ZnO@N-doped PPAC was obtained. • The cycle stability was achieved with a capacitance retention of 86% after 5000 cycles. [ABSTRACT FROM AUTHOR]

This study presented the electrochemical deposition of potassium nitrate-doped polypyrrole (Ppy:KNO 3) on stainless steel (SS), graphite sheet (GRs), and carbon fiber (CF) substrates, Ppy:KNO 3 /SS, Ppy:KNO 3 /GRs, and Ppy:KNO 3 /CF supercapacitor electrodes. Structural, morphological, and molecular analyses were conducted using X-ray diffraction (XRD), scanning electronic microscope (SEM), and Fourier transform infrared spectroscopy (FTIR). SEM images exhibited distinct morphologies of Ppy:KNO 3 films, varying with cycles, scan rates, and Ppy:KNO 3 concentrations. Ppy:KNO 3 /CF film displayed a unique structure with minimal particle aggregation. Electrochemical performance was assessed through Cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) measurements and electrochemical impedance spectroscopy (EIS). Notably, Ppy:KNO 3 /CF demonstrated a specific capacitance of 1020 F/g at 1 A/g. It exhibited 92 % capacitance retention after 1000 cycles, along with impressive power and energy densities of 310 W/kg and 71.2 Wh/kg, respectively. These results represented a significant progress in the development of high-performance, durable supercapacitors. [ABSTRACT FROM AUTHOR]

By using a one-step synthesis approach, 2,4,6-triamino-5-nitrosopyrimidine and 4,4'-biphenyldicarboxaldehyde were combined to create Schiff base polymer (TPB) and carbon nanotubes doping Schiff base polymers (TPB/MWCNTs-X, X = 2, 5, 8). Enhancement of electrochemical properties of Schiff base polymers (TPB) can be done by doping pretreated carbon nanotubes. Carbon nanotubes disrupted the π−π stacking of polymer molecular links and some microcosmic pore structures formed in the nanotubes doping process, and the carbon nanotubes are suitable for channeling of electrolyte ion diffusion from electrolyte solution body to the center of conductive polymer bulk. Scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy were used to characterize the morphology and phase compositions. Sample TPB/MWCNTs-2 possess the optimal electrochemical performance, measurement results reveal that the specific capacitance of TPB/MWCNTs-2 electrode is 714 F g−1 at a current density of 0.5 A g−1 in the three-electrode system, and the capacity retention rate is still 76.6% in 5000 cycles with 10 A g−1 current density. Furthermore, the asymmetric supercapacitor battery hybrid device (TPB/MWCNTs-2//AC) was established in 6 M KOH electrolyte with TPB/MWCNTs-2 and activated carbon (AC) serving as the positive and negative electrodes, respectively. The TPB/MWCNTs-2//AC device has the maximum energy density of 94.06 Wh kg−1 with 0.5 A g−1 current density; at the same time, the device possesses 371.87 W kg−1 power density. The introduction of carbon nanotubes into Schiff base polymers disrupts the internal π−π stacking and provides more oxidatively active sites, offering more paths for electrons to move. This work offers a novel approach to the synthesis of electrode materials from Schiff base conducting polymer-carbon nanotube composites with exceptional electrochemical characteristics. [ABSTRACT FROM AUTHOR]

This study aims to enhance the energy storage capabilities of flexible supercapacitors by fabricating graphene-doped MnO₂-coated carbon cloth electrodes through a hydrothermal method. This technique was selected for its ability to uniformly disperse MnO₂ nanorods (~ 50 nm thick) on carbon surfaces, while anchoring graphene plates at rod interfaces to improve conductivity. Comprehensive characterization including XRD, FTIR, SEM, and TEM confirmed the structural integrity of the electrodes. Electrochemical analysis (CV, GCD, and EIS) revealed a diffusion-controlled charge storage mechanism, achieving a specific capacitance of 513 F/g (205 F/cm3–1027 mF/cm2) at a current density of 1 A/g. The electrodes demonstrated impressive energy-power densities of 45.6 Wh/kg–200 W/kg and retained 87% of their initial capacity after 2500 cycles, indicating robust cyclic stability. Remarkably, the inclusion of graphene enhanced the performance nearly threefold compared to similar electrodes in the literature, making these materials highly promising candidates for next-generation supercapacitors. [ABSTRACT FROM AUTHOR]

This paper presents an approach to designing a supercapacitor (SC) module according to defined power profiles and providing a control algorithm for sharing the energy from the SC module and accumulator in a hybrid energy storage system (HESS). This paper also presents a view of a printed circuit board (PCB) of the SC module and an interconnection board between the bidirectional converter, accumulator, and SC module. The practical part of the paper presents the measurement of the voltages and currents on the SC module, accumulator, and output of the DC/DC converter to visualize the energy flow between them. [ABSTRACT FROM AUTHOR]

To enhance the inherent poor conductivity and low cycling stability of dimetallic layered double hydroxides (LDHs) materials, designing a synergistic effect between EDLC capacitors and pseudocapacitors is an efficient strategy. In this paper, we utilized a solvothermal technique employing Co‐glycerate as a precursor to prepare sea urchin‐like NiCo‐LDH hollow spheres anchored on a 3D graphene aerogel. The unique morphology of these hollow microspheres significantly expand the specific surface area and exposes more active sites, while reducing the volume changes of materials during long‐term charging and discharging processes. The 3D graphene aerogel serves as a conductive skeleton, improving the material's electrical conductivity and buffering high current. The sea urchin‐like NiCo‐LDH hollow spheres anchored on 3D graphene aerogel (H‐NiCo‐LDH@GA) has a specific surface area of 51 m2 g−1 and the ID/IG value is 1.02. The H‐NiCo‐LDH@GA demonstrate a significant specific capacitance of 236.8 mAh g−1 at 1 A g−1, with a remarkable capacity retention rate of 63.1 % even at 20 A g−1. Even after 8000 cycles at 10 A g−1, the capacity retention still remains at 96.3 %, presenting excellent cycling stability. [ABSTRACT FROM AUTHOR]

Designing potential architectures by the modification of conventional electrode materials is an effective approach in the development of high performance supercapacitor electrodes. The present study investigated the effect of varying anodization voltages (50, 75, and 100 V) on the morphology and electrochemical properties of titanium nanotubes (TNT). Molybdenum was doped onto TNT using a simple hydrothermal procedure, followed by thermal treatment at 450 °C. The study effectively demonstrated control over the dimensions of the nanotube structure by adjusting the anodization voltage. Additionally, it was found that the tube diameters were increased due to etching during the hydrothermal treatment with the Mo precursor, which potentially enhanced the supercapacitive performance of Mo‐doped TNT. Further, structural analysis revealed that Mo doping improved both crystallinity and electrode stability. With an optimal anodization voltage of 100 V, TNT and Molybdenum‐doped TNT could exhibit capacitance value of 13.34 and 326.54 mF cm−2 respectively, at a current density of 1 mA cm−2. Furthermore, the electrode demonstrated good cyclic stability with 88% capacitance retention and 97% coulombic efficiency after 5000 cycles. An impressive energy density of 87.03 µWh cm−2 and a power density of 799.99 µW cm−2 could be achieved with this sample in an asymmetrical device. [ABSTRACT FROM AUTHOR]

3D printing, a rapidly expanding domain of additive manufacturing, enables the fabrication of intricate 3D structures with adjustable fabrication parameters and scalability. Nonetheless, post‐fabrication, 3D‐printed materials often require an activation step to eliminate non‐conductive polymers, a process traditionally achieved through chemical, thermal, or electrochemical methods. These conventional activation techniques, however, suffer from inefficiency and inconsistent results. In this study, a novel chemical‐free activation method employing laser treatment is introduced. This innovative technique effectively activates 3D‐printed electrodes, which are then evaluated for their photo and electrochemical performance against traditional solvent‐activated counterparts. The method not only precisely ablates surplus non‐conductive polymers but also exposes and activates the underlying electroactive materials. The 3D‐printed electrodes, processed with this single‐step laser approach, exhibit a notably low overpotential of ≈505 mV at a current density of −10 mA cm−2 under an illumination wavelength of 365 nm. These electrodes also demonstrate exceptional durability, maintaining stability through >100 000 cycles in energy storage applications. By amalgamating 3D printing with laser processing, the creation of electrodes with complex structures and customizable properties is enabled. This synergy paves the way for streamlined production of such devices in the field of energy conversion and storage. [ABSTRACT FROM AUTHOR]

Electrochemical energy storage devices with high specific capacity are of utmost important for the next-generation electronic devices. Supercapatteries (SCs) are highly demanded energy storage devices nowadays as these bridge the low energy supercapacitors and low power batteries. Herein, we report a rapid synthesis of cobalt manganese phosphate (COMAP) by microwave-assisted hydrothermal method and facile fabrication of SCs using electrodes comprising of COMAP as positrode material. The effect of precursor concentration on the microstructure and surface morphology of the COMAP samples are examined initially. Further, the electrochemical performance of COMAP electrodes is studied systematically in 3 M KOH (aqueous) electrolyte. COMAP exhibits excellent charge storage capabilities where type of charge storage mechanism is found to be battery-type based on the calculation obtained from Dunn's method. The SC electrode fabricated with COMAP synthesized using cobalt: manganese precursor ratio as 80:20 exhibits a highest specific capacity of 191.4 C/g at a scan rate of 1 mV/s. An asymmetric SC (ASC) cell fabricated with COMAP as positrode and activated carbon (AC) as negatrode exhibits a specific capacity of 165.5 C/g at a current density of 1.8 A/g. The COMAP//AC ASC cell exhibits an energy density of 34.1 Wh/kg at a corresponding power density of 1875 W/kg at a current density of 1.8 A/g. [ABSTRACT FROM AUTHOR]

Metal organic frameworks (MOF's) have gained considerable attention in the field of energy storage and supercapacitors applications. Herein, we synthesized copper oxide (CuO) through the precipitation method and concurrently derived from the solvothermal prepared copper-benzene dicarboxylate (Cu-BDC) by calcination. The integration of MOF-derived nanostructures with traditional CuO to form a hybrid electrode material, has not been extensively explored. The synthesized materials were characterized using x-ray Diffractometry, FTIR, XPS, Brunauer, Emmett, and Teller and morphological analysis was conducted using scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM) affirming the composite's nature. Electrochemical impedance spectroscopy, galvanostatic charge–discharge, and cyclic voltammetry were used to evaluate the electrochemical properties of electrode material. With a specific capacitance of 691 Fg−1 for CuO obtained from Cu-BDC (benzene dicarboxylic acid) and 236 Fg−1 for CuO via the precipitation method, measured at a scan rate of 5 m Vs−1 in 6 M KOH was found to be the optimal performance solution for the electrode material. The mesoporous structures are crucial for their absorption ability and improved ion transport, resulting in optimized electrochemical performance. Finally, we demonstrate significant improvements in specific capacitance and cycling stability compared to pure CuO-based electrodes, highlighting the potential of this composite structure for advanced supercapacitor applications. [ABSTRACT FROM AUTHOR]

This new experimental design aims to develop an environmental protection concept based on the recycling of waste batteries, integrating inorganic chemistry, electrochemistry and analytical chemistry experiment system. It merges nickel-metal hydride battery recycling, secondary energy storage application with nickel ion analysis and detection, deepening students' understanding of basic chemistry experiment principles and expanding innovative thinking. In terms of secondary energy storage, cobalt-containing nickel hydroxide from nickel-metal hydride battery recycling solution and commercial activated carbon were selected as positive and negative electrode materials, respectively. The energy storage capacity of the device was verified by assembling the button cell. Chronopotentiometry and cyclic voltammetry were used to evaluate the performance of the button device at different current densities and different sweep rates. Meanwhile, multiple sets of button cells in series are used to light small bulbs to verify their practical application. In the aspect of nickel ion detection, spectrophotometry is used to quantitatively detect nickel ion content. Through the joint design and analysis of experiments, students can realize the potential application prospects of new energy technologies and fully understand the recycling of energy-storage devices and detection analyses, and thus cultivate innovation and environmental awareness. [ABSTRACT FROM AUTHOR]

This study presents the synthesis of TiO2‐graphene nanocomposites with varying mass ratios of graphene (2.5, 5, 10, 20 wt. %) using a facile and cost‐effective hydrothermal approach. By integrating TiO2 nanoparticles with graphene, a nanomaterial characterized by a two‐dimensional structure, unique electrical conductivity and high specific surface area, the resulting hybrid material shows promise for application in supercapacitors. The nanocomposite specimens were characterized by X‐ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman microscopy, field‐emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). Additionally, supercapacitive properties were investigated using a three‐electrode setup by cyclic voltammetry (CV), galvanostatic charge‐discharge (GCD) and electrochemical impedance spectroscopy (EIS) tests. Notably, the TiO2‐20 wt. % rGO nanocomposite exhibited the highest specific capacitance of 624 F/g at 2 A/g, showcasing superior electrochemical performance. This specimen indicated a high rate capability and cyclic stability (93 % retention after 2000 cycles). Its remarkable energy density and power density of this sample designate it as a strong contender for practical supercapacitor applications. [ABSTRACT FROM AUTHOR]

The design of multifunctional materials for energy storage and conversion systems is vital in addressing present global energy issues. In this work, we have prepared a highly active and economical hybrid material comprising ZnO and Nb2O5, integrated with g-C3N4 (Nb@ZGCN) through the simple chemical method followed by calcination process. The resultant Nb@ZGCN electrode delivered a specific capacitance of 122.3 F g−1 at a current density of 1 A g−1 and maintained 71% of its initial value at a current density of 4 A g−1 in a 6 M KOH electrolyte. This hybrid electrode exhibited superb cyclic stability of 105% even after 2000 cycles at 4 A g−1 with an increased coulomb efficiency than the first cycle which is close to 100%. Additionally, the prepared hybrid material was further applied for electrocatalytic hydrogen evolution reaction (HER), delivering a small overpotential of 252.1 mV to achieve a current rate of 10 mA cm− 2 along with long-term durability in a 1 M KOH medium. The synergistic interaction between the ZnO, Nb2O5 and graphitic carbon nitride in the hybrid structure leads to abundant electroactive sites that remarkably improve the supercapacitive and HER activities. These results suggest that the developed hybrid material can be further exploited as an electrode material for supercapacitor and water splitting applications. [ABSTRACT FROM AUTHOR]

The current study is concerned with understanding the synthesis and application of the diversified BaS3:La2S3:Dy1.8 dithiocarbamate sulphide by the single source precursor (SSP) approach. Analytical approaches were used to evaluate the optical, crystalline, vibrational crosslinking, morphological, and thermal properties of BaS3:La2S3:Dy1.8 chalcogenide. The synthesized chalcogenide has an average crystallite size of 16.35 nm and mixed phases, with a direct band gap energy of 3.9 eV. The study of functional groups revealed the presence of metal sulphide bonds. In terms of morphology, BaS3:La2S3:Dy1.8 chalcogenide has an uneven shape with a small amount of aggregation. The electrochemical charge storage behavior of BaS3:La2S3:Dy1.8 was studied using a nickel foam electrode. The trichalcogenide-decorated electrode exhibited charge-storing behavior, with a specific capacitance of 723 F g− 1 determined by cyclic voltammetry. The electrode has a specific power density of 11,166 W kg− 1 and a low series resistance of 0.9 Ω, as shown by impedance measurements. [ABSTRACT FROM AUTHOR]

The increasing demand for sustainable and efficient energy storage materials has led to significant research into utilizing waste biomass for producing activated carbons. This study investigates the impact of the structural properties of activated carbons derived from various lignocellulosic biomasses—barley straw, wheat straw, and wheat bran—on the electrochemical performance of supercapacitors. The Fourier Transform Infrared (FTIR) spectroscopy analysis reveals the presence of key functional groups and their transformations during carbonization and activation processes. The Raman spectra provide detailed insights into the structural features and defects in the carbon materials. The electrochemical tests indicate that the activated carbon's specific capacitance and energy density are influenced by the biomass source. It is shown that the wheat-bran-based electrodes exhibit the highest performance. This research demonstrates the potential of waste-biomass-derived activated carbons as high-performance materials for energy storage applications, contributing to sustainable and efficient supercapacitor development. [ABSTRACT FROM AUTHOR]

With its distinctive multiple electrochemical reaction, iron vanadate (FeV3O9.2.6H2O) is considered as a promising electrode material for energy storage. However, it has a relatively low practical specific capacitance. Therefore, using the low temperature sol–gel synthesis process, transition metal doping was used to enhance the electrochemical performance of layered structured FeV3O9.2.6H2O (FVO). According to this study, FVO doped with transition metals with larger interlayer spacing exhibited superior electrochemical performance than undoped FVO. The Mn-doped FVO electrode showed the highest specific capacitance and retention of 143 Fg−1 and 87%, respectively, while the undoped FVO showed 78 Fg−1 and 54%. [ABSTRACT FROM AUTHOR]

The Co3O4 nanowire@NiCo2O4 nanosheet hierarchical array was constructed on Ni foam using hydrothermal and annealing approaches in turn, from which a NiCo2O4 nanosheet could self-assemble on the Co3O4 nanowire. The structure and morphology of the Co3O4 nanowire@NiCo2O4 nanosheet hierarchical array were characterized via XRD, EDS, SEM, and FESEM, respectively. The electrochemical performance of the composite array was measured via a cyclic voltammetry curve, galvanostatic current charge–discharge, charge–discharge cycle, and electrochemical impedance and then compared with the Co3O4 nanowire. The results show that the Co3O4 nanowire@NiCo2O4 nanosheet hierarchical array could reach a high value of 2034 F g−1 at a current density of 2.5 A g−1. After 5000 galvanostatic charge–discharge cycles, the specific capacitance of the Co3O4 nanowire@NiCo2O4 nanosheet hierarchical array could still maintain 94.7% of the original value. Therefore, the Co3O4 nanowire@NiCo2O4 nanosheet hierarchical array would be a desirable electrode material for a high-performance supercapacitor. [ABSTRACT FROM AUTHOR]

The controlled synthesis of precise carbon nanostructures with high electron conductivity, high reaction activity, and structural stability plays a significant role in practical applications yet largely unmet. Metal-organic frameworks (MOFs), covalent organic frameworks (COFs), and coordination polymers (CPs) as crystalline porous materials (CPMs) have shown extraordinary porosity, tremendous structural diversity, and highly ordered pores, offering a platform for precise controlled carbon materials (CMs) with regular porous structures and high performances. Some recent studies have shown that CMs derived from CPMs with high specific surface area, superior chemical stability, excellent electrical conductivity offer a great opportunity for electrochemical energy storage and conversion. In this review, we summarize recent milestones of CPMs derived CMs in the field of capacitive energy storage. We hope the more precise design and control at the atomic level of CPMs could provide us a constructive view of the structure-activity relationship between CMs and electrochemical capacitors, as well as future trends and prospects. [ABSTRACT FROM AUTHOR]

Effective wastewater treatment remains a critical challenge, especially when dealing with hazardous pollutants like antimony (Sb(III)). This study addresses this issue by using innovative nanocomposites to remove Sb(III) ions from water, while simultaneously repurposing the spent adsorbents for energy storage applications. We developed reduced graphene oxide-NiFe2O3-SiO2-polyindole nanocomposites (RGO-NiFe2O3-SiO2-PIn NCs) via a hydrothermal synthesis method, achieving a high removal efficiency of 91.84% for Sb(III) ions at an initial concentration of 50 mg/L at pH 8. After adsorption, the exhausted adsorbent was repurposed for energy storage, effectively minimizing secondary pollution. The Sb(III)-loaded adsorbent (RGO-NiFe2O3-SiO2-PIn@SbOx) exhibited excellent performance as an energy storage material, with a specific capacitance (Cs) of 701.36 F/g at a current density of 2 A/g and a retention rate of 80.15% after 10,000 cycles. This dual-purpose approach not only advances wastewater treatment technologies but also contributes to sustainable and economical recycling practices, particularly in the field of energy storage. [ABSTRACT FROM AUTHOR]

This investigation focused on the fabrication of ceramic ferrimagnetic CuFe2O4–conductive polypyrrole (PPy) composites for energy storage. CuFe2O4 with a crystal size of 20–30 nm and saturation magnetization of 31.4 emu g−1 was prepared by hydrothermal synthesis, and PPy was prepared by chemical polymerization. High-active-mass composite electrodes were fabricated for energy storage in supercapacitors for operation in a sodium sulfate electrolyte. The addition of PPy to CuFe2O4 resulted in a decrease in charge transfer resistance and an increase in capacitance in the range from 1.20 F cm−2 (31 F g−1) to 4.52 F cm−2 (117.4 F g−1) at a 1 mV s−1 sweep rate and from 1.17 F cm−2 (29.9 F g−1) to 4.60 F cm−2 (120.1 F g−1) at a 3 mA cm−2 current density. The composites showed higher capacitance than other magnetic ceramic composites of the same mass containing PPy in the same potential range and exhibited improved cyclic stability. The magnetic behavior of the composites was influenced by the magnetic properties of ferrimagnetic CuFe2O4 and paramagnetic PPy. The composites showed a valuable combination of capacitive and magnetic properties and enriched materials science of magnetic supercapacitors for novel applications based on magnetoelectric and magnetocapacitive properties. [ABSTRACT FROM AUTHOR]

There is a pressing need for flexible integrated systems owing to the swift progress of flexible electronics. Apart from flexibility, flexible supercapacitor (FSC) integrated systems exhibit certain characteristics like rapid charge–discharge rates, high power density, and excellent cycling stability, which makes them a promising candidate to serve as a vital component in flexible electronics. In this context, an in‐depth overview of recent progress in FSC‐integrated systems, including their design of structure, materials, fabrication techniques, and applications, is offered. On the basis of the current progress, the existing challenges and future prospects are also outlined and discussed. [ABSTRACT FROM AUTHOR]

The molten‐salt synthesis and electrochemical capacitive behaviors of porous carbon are reported using anthracite as the precursor. Upon synthesis, the binary KCl/K2CO3 molten salt not only exfoliates bulky anthracite to carbon nanosheets but also creates rich micro‐ and mesopores in the structure. The resulting porous carbon shows a large surface area of 1399.7 m2 g−1 and a total pore volume of 1.50 cm3 g−1. In 6.0 mol L−1 KOH aqueous electrolyte, it delivers a high specific capacitance of 245.6 F g−1 at a current density of 0.5 A g−1. Flexible micro‐supercapacitors with this porous carbon are assembled following an interdigitated design. The micro‐supercapacitor affords an area capacitance of 18.0 mF cm−2 and an energy density of 1.58 µWh cm−2 at a power density of 20 µW cm−2, and sustains 89.6% of the capacitance after 2000 cycles. Furthermore, the strain sensor fabricated by replacing the current‐collecting fluid at both ends of the electrode provides consistent and stable signal output, regardless of the degree of bending and the number of cycles. This study demonstrates the great potential of anthracite‐based porous carbon in flexible energy and electronic microdevices. [ABSTRACT FROM AUTHOR]