Biomass-derived carbon materials are increasingly being explored for energy storage applications due to their environmental compatibility, renewability, and cost-effectiveness. This work proposes a sustainable strategy to address the growing demand for green energy storage systems by converting agricultural waste into high-performance supercapacitor electrodes. Activated carbon was prepared from bagasse obtained from Maranta arundinacea (arrowroot tuber, ART), selected for its low cost, abundant availability, and potential to enhance power delivery characteristics. The ART bagasse was first carbonised at 800 °C under a nitrogen atmosphere to obtain the carbon material (AR). Subsequent activation was performed at 600, 700, 800, and 900 °C, yielding samples denoted AR 600, AR 700, AR 800, and AR 900, respectively. Comprehensive structural and surface characterisation was performed using XRD, Raman spectroscopy, FT-IR, FE-SEM, HR-TEM, BET, and XPS analysis. Among the prepared materials, AR 800 exhibited the highest specific surface area of 2553 m2 g− 1, as determined by BET analysis. Electrochemical measurements revealed that AR 800 delivered superior capacitive performance, achieving a specific capacitance of 336 F g− 1 at a current density of 1 A g− 1 in a three-electrode system. This optimized material was further assembled into a symmetric supercapacitor device, which demonstrated a specific energy of 7.4 Wh kg− 1 and a specific power of 1300 W kg− 1 at 1 A g− 1. The device maintained 95.4

Abstract The orthorhombic Nb2O5 and α-Fe2O3 composite exhibits strong intercomponent synergy, making it a promising candidate for high-performance supercapacitor applications. In the present study, orthorhombic Nb2O5 and α-Fe2O3 composites were synthesized at the ratios 1:1, 1:2, and 2:1 (NFO11, NFO12, and NFO21). The as-prepared samples were subjected to various physicochemical characterization to confirm their structure, surface morphology, and surface chemical environment. The NFO12 electrode exhibits the highest specific capacitance of 220 F g–1 at a current density of 1 A g–1, surpassing all other electrode materials. NFO12 and activated carbon (AC) materials on a graphite sheet were sandwiched to fabricate an asymmetric supercapacitor (NFO12// AC), which delivers specific energy and specific power of 15 Wh kg–1 and 916 W kg–1, respectively. The fabricated devices were tested by glowing the different voltage LED bulbs. Additionally, a flexible asymmetric supercapacitor (FASC) device was fabricated using carbon cloth as the substrate, which exhibits specific energy and specific power of 20 Wh kg–1 and 900 W kg–1, respectively. Furthermore, excellent cyclic stability, with 94% Coulombic efficiency and 93% capacitance retention, was achieved at a zero-degree (nonbending) angle even after 10,000 cycles. Similarly, the FASC device at a 180-degree bending angle shows 93% Coulombic efficiency and 92% capacitance retention even after 10,000 cycles. FASC devices were examined under various stressed conditions to substantiate the flexibility behavior.

Ti3C2 MXene is a highly conductive 2D transition metal carbide that has gained significant attention for its layered architecture, tunable surface chemistry, and outstanding mechanical properties. These characteristics make it a promising candidate for batteries, supercapacitors, electrocatalysis, and other energy devices. Despite these advantages, practical deployment of MXenes is hindered by oxidation and moisture-driven degradation that impair microstructure and long-term stability, as well as aggregation and self-restacking of multilayer flakes during fabrication, which reduce accessible surface area and impair ion transport. These challenges reduce the active contact area for ion access and reaction sites, leading to sluggish charge transfer, lower capacitance, inferior performance, and diminished efficiency in energy storage and conversion applications. To address these issues, Ti3C2 is integrated with various carbon nanostructures and carbon forms, such as quantum dots, graphene, carbon nanotubes, activated carbon, and amorphous carbon, that exploit the synergistic effects of MXenes high pseudocapacitance and electrical conductivity with carbon supports mechanical flexibility, high surface area, and environmental stability. This review summarizes recent advances in MXene/carbon composites engineered to enhance their charge storage and conversion performance across a range of applications, including supercapacitors, batteries, electrocatalysis, solar cells, and CO2 conversion. The insights provided aim to advance the development of durable, high-performance Ti3C2 MXene/carbon composites for sustainable energy technologies.

Metal-sulfur (M-S) batteries are promising candidates to conventional lithium-ion (Li-ion) technology, yet their commercialization is hindered by the polysulfide shuttle effect. Designing efficient polysulfide-trapping hosts is therefore critical. In this work, we investigate spirographene (SG), a novel 2D material, as a polysulfide host for M-S (M = Li, Na) batteries. Pristine-SG shows stronger affinity for insoluble polysulfides, while nitrogen doping enhances binding with soluble species. Remarkably, boron doped SG (B-SG) achieves a balanced approach, exhibiting moderate adsorption energy for both soluble and insoluble polysulfides, making it a more versatile material candidate. Bader charge analysis reveals a significant charge transfer (similar to 0.9 e for Li-S and 0.88 e for NaS), particularly short chain M2S2 species, highlighting strong electron coupling. COHP calculations further show that B-SG exhibits more negative integrated COHP values for C-S and C-Li/Na bonds, confirming enhanced chemical anchoring. This strong interaction accelerates discharge kinetics: The Gibbs free energy barrier for the rate-determining sulfur reduction step is lowered to 0.93 eV in Li-S and 0.29 eV in Na-S systems. These reduced energy barriers suggest faster and more efficient reaction pathways. Consequently, the combination of strong polysulfide adsorption, enhanced conductivity, and improved decomposition kinetics of B-SG suggest its potential to mitigate the shuttle effect and improve M-S battery performance. Overall, doped SG offers a synergic strategy for stabilizing polysulfides and enhancing the electrochemical performance of next-generation M-S batteries.

The growing demand for energy storage solutions has necessitated the development of advanced materials with high efficiency, sustainability, and cost-effectiveness. This study explores the recycling of waste batteries into nitrogen-doped reduced graphene oxide (N-RGO) incorporated with boron nitride (BN) nanosheets for supercapacitor applications. The synthesis process involves a sustainable Electrochemical Exfoliation, Modified Hummer’s and simple sonication methods which enabling the recovery of valuable carbon-based materials from waste batteries and their functionalization with nitrogen. Electrochemical analysis of N-RGO/BN composite shows excellent specific capacitance and lower charge transfer resistance for three electrode configurations. In full cell, the device achieved excellent specific capacitance of 86 F g−1, specific energy of 12 Wh kg−1 and specific power of 200 W kg−1 with capacitance retention of 88 % and 95 % of coulombic efficiency even after 10,000 cycles in coin cell configuration. The results highlight the potential of recycling waste batteries into functional materials for sustainable energy storage systems, contributing to both environmental preservation and technological advancement.

Transition-metal chalcogenides and rare-earth elements are extensively used in energy storage applications as electrode materials because of their good electrical conductivity, thermal and mechanical stability, and flexibility. In this study, cerium oxysulphide/nickel sulphide [Ce4O4S3/Ni3S2] (CSNS) composites were synthesized by a hydrothermal method using cerium and nickel at three different metal ratios, represented as CSNS (1 : 1), CSNS (1 : 2), and CSNS (2 : 1). XRD analysis of the prepared materials confirmed the formation of a Ce4O4S3/Ni3S2 composite crystal structure. SEM analysis revealed aggregated clusters of rod-shaped, sphere-shaped, and non-uniform granules for CSNS (1 : 1), (1 : 2), and (2 : 1), respectively. XPS analysis of the CSNS (2 : 1) composite revealed binding energies of 168 eV, 531.25 eV, 855.69 eV, and 885.76 eV, attributed to S 2p, O 1s, Ni 2p, and Ce 3d elements, respectively. The aggregation of the granules was confirmed by transmission electron microscopy (TEM) for CSNS (2 : 1). BET analysis indicated a mesoporous material, with the highest surface area (39.89 m2 g-1) and pore diameter (40.63 nm) observed for the CSNS (2 : 1) composite among all the prepared samples. The electrochemical properties of the materials were assessed using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) analysis, and electrochemical impedance spectroscopy (EIS). A symmetric supercapacitor device was fabricated with the CSNS (2 : 1) composite that showed a high specific capacitance of 67 F g-1, a specific energy of 18 Wh kg-1, and a specific power of 1399 W kg-1 at a specific current of 0.5 A g-1. Furthermore, the device withstands up to 5000 cycles, shows 99% coulombic efficiency and 85% capacitance retention.

High-temperature superconducting coils subjected to ultra-high magnetic fields undergo mechanical deformation due to the Lorentz force generated by the magnetic field. Recent attempts to prevent this deformation have proposed the use of overbanding technology, which entails surrounding the outermost turn of the coil with a high-strength material such as stainless steel, as an optimal alternative. However, the disadvantage of overbanding in terms of thermal/electrical protection of the coil has been emphasized because the stainless steel surrounding the coil reduces the operating efficiency of the coil by preventing the dissipation of joule heat and current when quenched. In this study, our approach to prevent the deformation of the coil without applying such overbanding was to intentionally abrade the surface of the high-temperature superconducting tape using sandpaper with different friction coefficients. This enabled us to fabricate coils with different turn-to-turn friction forces, which prevented the deformation of the coil by using the turn-to-turn friction force generated by the abrasion. The electromechanical tests we performed on the coil in a liquid nitrogen bath (77 K) confirmed that, compared to the coil without surface treatment, the coils fabricated by abrading the surfaces of the high-temperature superconducting tape exhibited decreased deformation even when the same Lorentz force was applied.

The growing demand for efficient energy storage systems has intensified the search for advanced electrode materials for supercapacitors. A key challenge lies in developing materials that simultaneously offer high specific capacitance, fast charge–discharge capability, long-term stability, and cost-effectiveness. Cerium-based materials, with variable oxidation states, provide excellent redox activity and chemical stability, while nickel enhances electrical conductivity and charge transfer. Chalcogenides of cerium and nickel are attractive due to their favorable electrochemical properties, environmental friendliness, and affordability. In this study, CeSe1.9/CeSe/Ni3Se4 (CENSE) composites were synthesized via the hydrothermal method using different Ce:Ni molar ratios, such as CENSE (1:1), CENSE (1:2), and CENSE (2:1) to evaluate their suitability as symmetric supercapacitor electrodes. X-ray diffraction confirmed phase formation. Morphological analysis using FESEM showed aggregated spherical particles in CENSE (1:1) and (2:1), while CENSE (1:2) exhibited irregular granules. XPS of CENSE (1:2) displayed characteristic binding energies for Se 3d, Ni 2p, and Ce 3d. HRTEM confirmed the irregular spherical structure, and BET analysis indicated mesoporosity with a surface area of 30.57 m2/g and pore size of 48.38 nm. Electrochemical studies, including cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS), revealed that the CENSE (1:2) electrode delivered superior performance. The corresponding symmetric device achieved a specific capacitance of 28 F/g, specific energy of 9 Wh/kg, and specific power of 747 W/kg at 0.5 A/g, with 95

A Ce 4 O 4 S 3 /Ni 3 S 2 composite made via hydrothermal synthesis shows a specific capacitance of 144 F g −1 at 1 A g −1 . The CSNS (2 : 1) supercapacitor retains 85% capacitance, 95% efficiency after 5000 cycles, with 18 Wh kg −1 energy and 1399 W kg −1 power at 0.5 A g −1 .

Cost effective and complication-free wet chemical co precipitation protocal was employed to prepar Ni-Sn-layered double hydroxide and NiO/SnO2 nanocomposites. Fundamental characterizations were done to evaluate structural, optical, morphological and dielectric behaviours. Cubic and tetragonal structures were witnessed for NiO and SnO2 via XRD analysis respectively. Allowed direct band gap nature was revealed from the optical absorption study and the calculated bandgap values were 3.29, 3.39, 3.09 and 3.20 eV for NiO. SnO2, NiO/SnO2, and Ni-Sn-LDH respectively. Surface features, stacked layered nanosheet arrangements and textural properties of the high-performance electrode materials were witnessed from SEM and HRTEM analyses. The composite materials, NiO/SnO2 and Ni-Sn-LDH nanosheet, demonstrate an enhanced capacitance per unit area and superior capacitance retainable nature with numerical values of 821 F/g for 5mV/s scanning for NiO/SnO2 sample. For 1 A per gram electric current density NiO/SnO2 exhibited a capacitance of 99.2 % retentively beyond 300 consecutive cycles. High surface area and large active site densities of this electrode material enabled it to exhibit such performance with respect to charge storage, enhanced charge/discharge rates and long-term stability. The Ni-Sn-LDH electrode exhibited 315 F/g of capacitance per unit area at 5 mV/s scan rate. Appreciable retentive capacitance (98.01 %) and one ampere per gram beyond 300 cycles was shown by Ni-Sn LDH. Morphological dependent (granular structured layers) carbon-free stain less steel electrode supercapacitance properties were revealed from the present work.

Transition metal-based chalcogenide (TMX) has multiple valence states, a high surface area, excellent electronic conductivity, and electrochemical activity with various applications. Nickel sulfide/tungsten disulfide (NiS/Ni3S4/WS2) (NWS) composites are synthesized with three different metal ratios (1:1, 1:2, 2:1) by a two-step solvo-hydrothermal method. The binary NWS composites are enriched with numerous metal active sites to enhance their electrochemical behavior. Half-cell configurations help analyze the electrochemical performance of the NWS composite electrode material. Compared to the as-prepared samples, the NWS (1:1) composite electrode showed the highest specific capacitance of 1,475 F g-1 at a specific current of 1 A g-1, respectively. The hybrid supercapacitor (HSC) is fabricated using N-doped graphene (NG) as the negative electrode and NWS (1:1) composite as the positive electrode with an aqueous electrolyte of 3 M KOH. The fabricated NG//NWS (1:1) device exhibits a specific energy of 39.25 Wh kg-1 with a specific power of 750 W kg-1 at a specific current of 1 A g-1. An NWS (1:1) composite is also applied in an aqueous Zn-Ni battery as a positive electrode and a zinc-deposited graphite sheet (Zn@GS) as a negative electrode, which delivers a specific energy of 171 Wh kg-1 at the specific power of 5.7 kW kg-1.

In this work, we designed a metal-organic framework (MOF) derived cobalt nanoparticles encapsulated nitrogenrich carbon with nickel iron-layered double hydroxide (Co-NC@NiFe-LDH) for real time electrochemical analysis of the antioxidant flavonoid-rutin (RUT). The prepared composite was examined by various analytical techniques, cyclic voltammetry, and differential pulse voltammetry. A glassy carbon electrode (GCE) modified with Co-NC@NiFe-LDH (Co-NC@NiFe-LDH/GCE) exhibited superior response for RUT along with excellent reproducibility, sensitivity, and selectivity which is attributed to the synergistic effects between the Co-NC and NiFeLDH, and enable excellent electron transfer across the electrode-electrolyte interface. The Co-NC@NiFe-LDH/ GCE responds linearly to RUT concentrations of 0.01 - 20.10 mu M and 20.10 - 267.31 mu M, with a limit of detection (LOD) and higher sensitivity of 5 nM and 11.898 mu A mu M-1 cm-2, respectively. These exceptional features of Co-NC@NiFe-LDH arise from its significant active sites, substantial surface area, and excellent electrolyte accessibility. The Co-NC@NiFe-LDH/GCE offers improved stability, with the initial oxidation peak current decreasing by <= 5% over 25 days of air exposure. The sensor demonstrated substantial recovery levels of 96.99 98.70%, 96.15 - 99.76%, and 97.86 - 99.74% for real-time analyses of serum, urine, and medicinal samples. This study paves the way for advanced sensing platforms in biomedicine and clinical applications, capitalizing on nanohybrid design.

In this study, the synthesis of magnesium-doped copper ferrite, namely CuxMg1-xFe2O4 (x = 1, 0.9, 0.7, and 0.5), is achieved using a facile microwave route, and the cubic crystalline structure, functional group, and nanostructured materials are discussed. The electrochemical studies of the magnesium-doped copper ferrite (MCF) are carried out by assembling a three-electrode conventional electrochemical cell with MCF samples as working electrode, a platinum wire as counter electrode, a silver (Ag)/silver chloride (AgCl) as reference electrode, and 2 M KOH aqueous solution as electrolyte. The study of the electrochemical performance of Mg-doped and undoped copper ferrite electrodes reveals that they show battery-type behavior with the transfer of two electrons (Mg to Mg2+) in 2 M KOH electrolyte in the potential window of 0.45 V to 0.35 V. Further, un-oxidized MgO oxidizes, leading to a quasi-conversion reaction. Additionally, the electrode (MCF) exhibits a greater specific capacity of 737.5 F g-1 at 1 A g-1. It is found that the MCF3 electrode retains 70% of its initial capacitance, which is higher than the CF electrode (33%), after 4000 continuous galvanostatic charge/discharge (GCD) cycles. An asymmetric supercapacitor cell is fabricated using MCF as the positive electrode, activated carbon (AC) as the negative electrode, 2 M KOH as the electrolyte, and polypropylene as the separator. The fabricated MCF//AC supercapacitor yields maximum specific energy of 62.61 W h kg-1 at specific power of 1168 W kg-1. These electrochemical features suggest that MCF is a feasible candidate material for developing supercapacitor electrodes.

One-dimensional (1D) Tetra-Penta-Hepta graphene nanoribbon (TPH-GNR) is an enticing material because of its distinctive structural and electrical characteristics. Using first -principles calculations, we investigate hydrogen molecules (H-2) storage on alkali metal (M = Li and Na)-decorated TPH-GNR. The initial results indicate that the adsorption of H-2 on pristine TPH-GNR is weak (-0.09 eV/H-2). However, alkali metal decoration significantly enhances the adsorption strength. Ab initio molecular dynamics simulations confirm the thermal stability of alkali metal -decorated TPH-GNR. We further analyze the charge transfer mechanism and density of states, which reveal a strong polarization of the H-2 molecules. Our study also reveals that 4 M@TPH-GNR exhibits gravimetric densities of 7.75 % (Li) and 6.90 % (Na), indicating the potential of TPH-GNR as an effective substrate for H-2 storage. Furthermore, a thermodynamic evaluation is conducted to examine the absorption and release of H-2 under practical operating conditions. Our findings suggest that alkali metal-decorated TPH-GNR can serve as a prospective material for efficient H-2 storage.

BiFeO3/Bi25FeO40 (BFO) and zinc-substituted BiFeO3/Bi25FeO40/Bi38ZnO(58) (BFZO1, BFZO2, and BFZO3) were successfully synthesized by a hydrothermal method at different concentrations of Zn:Fe. The BFZO1 showed the highest electrochemical behavior than other composites. The X-ray diffraction and Raman analyses of BFZO1 confirmed the formation of zinc-substituted BiFeO3/Bi25FeO(40)/Bi38ZnO58. The structural analysis confirmed the agglomerated flake-like morphology from field emission scanning electron microscopy and transmission electron microscopy. BFZO1 showed a high surface area of 56.59 m(2)g(-1) and a high pore diameter of 6.71 nm, offering a higher specific capacitance of 1087 F g(-1) at a current density of 1 A g(-1) in 3 M KOH as an electrolyte. Furthermore, the symmetric device fabricated from BFZO1 showed the highest specific capacitance of 236 F g(-1), a specific energy of 32 W h kg(-1), and a specific power of 1000 W kg(-1) at a current density of 0.5 A g(-1). The reversibility and cyclic stability of the device showed capacitance retention of 84% and Coulombic efficiency of 91% up to 10,000 cycles at a current density of 3 A g(-1). The resulting BFZO1 delivers excellent electrochemical performance in supercapacitor applications.

Transition metal chalcogenides (TMX) have attracted energy researchers due to their role as high-performance electrode materials for energy storage devices. A facile one-pot hydrothermal technique was adopted to synthesize a molybdenum disulfide/cadmium sulfide (MoS2/CdS) (MCS) composite. The as-prepared samples were subjected to characterization techniques such as XRD, FT-IR, SEM, TEM, and XPS to assess their structure, morphology, and oxidation states. The MoS2/CdS (MCS) composites were prepared in three different ratios of molybdenum and cadmium metals. Among them, the MCS 1:2 (Mo:Cd) ratio showed better electrochemical performance with a high specific capacitance of 1336 F g(-1) (high specific capacity of 185.83 mAh g(-1)) at a specific current of 1 A g(-1) for half-cell studies. Later, a hybrid supercapacitor (HSC) device was fabricated with N-doped graphene (NG) as an anode and MCS (1:2) as a cathode, delivering a high specific energy of 34 Wh kg(-1) and a specific power of 7500 W kg(-1). The high nitrogen content in the MoS2 structure in MCS composites alters the device's performance, where CdS supports the composite structure through its conductivity and encourages the easy accessibility of ions. The device withstands up to 10 000 cycles with a higher Coulombic efficiency of 97% and a capacitance retention of 90.25%. The high-performance NG//MCS (1:2) HSC may be a potential candidate alternative to the existing conventional material.

BiFeO3/Bi25FeO40 and cobalt doped Bi25FeO40/ BiFeO3 are synthesized by a cost-efficient hydrothermal technique. Cobalt is doped at four different concentrations of 1.5, 2.5, 3.5, and 4.5 mmol in a bismuth ferrite composite (BFCO1, BFCO2, BFCO3, and BFCO4). The capacitive behavior of BFCO3 is significantly higher than those of BFO, BFCO1, BFCO2, and BFCO4 based on their structure, morphology, and electrochemical properties. XRD confirmed the formation of a rhombohedral structure of BiFeO3 and cubic crystal structure of Bi25FeO40 and cobalt doped Bi25FeO40/BiFeO3 composites. Raman modes confirm the presence of cobalt doped Bi25FeO40/BiFeO3 in BFCO3. Microsized particles of BFCO1 were broken upon increasing the concentration of cobalt ion in BFCO2, BFCO3, and BFCO4. In BFCO3, the length of the needle is 0.45 mu m and breadth is 0.06 mu m, which spread over the spherical-shaped particles with an average size of 0.43 mu m. The surface area and average pore diameter of BFCO3 are 60.25 m2/g and 3.38 nm, which are relatively higher than the surface area and average pore diameter of BFO, BFCO1, BFCO2, and BFCO4. The capacitive behavior of BFCO3 shows a significantly higher specific capacitance of 605.16 F g-1 at a current density of 1 A g-1 under 3 M KOH as electrolyte in a three-electrode configuration. The symmetric device of BFCO3 exhibits higher specific capacitance of 176.87 F g-1, specific energy of 35.36 Wh kg-1, and specific power of 1199.43 W kg-1 at a current density of 0.5 A g-1 with super long cyclic stability of about 87% capacity retention, and the coulombic efficiency is about 96% even after 10,000 cycles.

This paper methodically reported the photocatalytic properties of TiO2 thin films with high transparency and a mesoporous structure, which were synthesized by manipulating templating with cellulose nanocrystals (CNC) and doping with Nb. The TiO2 precursors containing CNC and Nb chloride were synthesized through the sol–gel route, followed by spin coating on an indium tin oxide substrate with subsequent calcination for 1 h at 400 °C. The porous structure, phase composition, optical and morphological properties, and photocatalytic degradation activity of prepared materials were evaluated. The templated CNC played a major role in generating rod-like porous channels in TiO2 film, providing a mesoporous structure, as well as enhancing the heterogeneous nucleation rate of anatase phase with an average crystallite size of 9.95 nm. The anatase phase was stabilized and the surface area of TiO2 with 76.7 m2/g increased up to 127.3 m2/g with the aid of CNC templating and Nb doping into the TiO2. The light absorption capacity of the CNC templated TiO2 film doped with 5 at

Generally, white light-emitting diodes (LEDs) are fabricated by combining blue LED chips with yellow phosphors. When fabricating white LEDs, the phosphor is typically mixed with an organic resin and applied to the LED chips as a paste. A phosphor-in-glass (PiG) plate can alternatively be used to address the poor high temperature reliability of the paste method. However, because pores form in the PiG plate during the sintering process, this method results in a loss of optical efficiency. Accordingly, we aimed to improve the fluidity of glass and light efficiency by optimizing the sintering temperature of the glass powder and the phosphor content respectively for reducing internal porosity in the PiG. In this study, glass powder was sintered at different temperatures to produce glass plates, while also varying the phosphor content to fabricate PiG plates. The optimal light characteristics were realized with a glass sintering temperature of 640 degrees C and a phosphor content of 20 wt%.