Flexible and high-performance sodium-ion storage systems are essential for next-generation energy technologies. Here, orthorhombic K(VO2)2(PO4) nanostructures were synthesized on carbon cloth through a controlled phosphorization process for 4 h (4KVOP-C). The 4KVOP-C electrode exhibited a fibrous network morphology, providing abundant active sites, short Na+ diffusion pathways, and strong contact with the conductive substrate. Moreover, its robust P-O bonds and open ion-diffusion channels enhanced its structural stability and charge transport. The 4KVOP-C electrode delivered outstanding electrochemical performance, with a high areal capacitance and excellent rate capability in a three-electrode configuration. The phosphate-stabilized vanadyl framework of KVOP enables delocalized charge redistribution across the V-O-P networks during Na adsorption, resulting in a higher quantum capacitance and density of states at the Fermi level. This electronic preconditioning underlies its superior areal capacitance, fast charge-discharge, and enhanced Na-ion accommodation compared with those of potassium-intercalated vanadium oxide. Moreover, a symmetric 4KVOP-C//4KVOP-C supercapacitor was assembled, which operated over a wide voltage window of 2.0 V, achieving an energy density of 50 & micro;W h cm-2 at a power density of 1980 & micro;W cm-2, along with excellent cycling stability. These results demonstrate that the fibrous K(VO2)2(PO4) nanostructures synthesized via optimized phosphorization exhibit excellent intrinsic electrochemical properties, making them potential electrode materials for flexible, high-energy-density and durable sodium-ion supercapacitors.

Exploring heterostructured multimetal oxides holds incredible potential to greatly boost supercapacitor (SC) performance through the facile integration of two distinct materials. The performance characteristics of these sophisticated electrode materials exceed those of conventional single counterparts. Herein, we present a hierarchical NiMoO4/CoMoO4 (NM/CM-O) heterostructure with a well-defined nanosheet-array architecture (NSAs). This facile structure was grown on a nickel foam framework, enabling its use as a battery-type electrode material. The cohesive architecture of the resulting material allows it to function as a binder-free SC electrode, exhibiting markedly enhanced electrochemical performance. This design optimizes the density of redox-active sites, enhances interfacial charge-transfer efficiency, and minimizes ion-diffusion distances. Furthermore, pronounced synergistic interactions between the two components, together with the involvement of multivalent ions, enhance electrochemical performance. Interestingly, the NM/CM-O heterostructure NSAs, functioning as a binder-free electrode, exhibit an impressive specific capacity of 704C/g at 1 A/g, surpassing that of the individual constituent electrodes. Moreover, a hybrid SC (HSC) was constructed using NM/CM-O and activated carbon (AC) as the positrode and negatrode, respectively. This NM/CM-O//AC HSC demonstrated impressive performance, achieving a power density of 20.3 kW/kg and an energy density of 76.4 Wh/kg. Notably, it exhibited excellent durability, experiencing only a 6.9% capacitance loss after enduring 20,000 charge/discharge cycles. The proposed investigation into the engineering of a multi-redox-active-site heterostructure is expected to enable substantial advances in renewable energy technologies.

This study presents the synthesis of Co0.85Se microsphere-like structures on nickel foam (NF) substrates for high-performance HSC applications. The Co0.85Se microspheres were synthesized using a two-step hydrothermal process, yielding well-distributed—albeit non-uniform—structures on the NF substrate. The electrochemical performance of the Co0.85Se/NF electrode, evaluated in a three-electrode system, demonstrated remarkable characteristics, including a high specific capacity of 719 C g−¹ at 1 A g⁻¹ and outstanding long-term cycling stability, with 87.1% capacity retention over 10,000 charge-discharge cycles. To assess the practical applicability of the Co0.85Se/NF electrode, a hybrid supercapacitor device was assembled using activated carbon (AC) as the negative electrode and Co0.85Se/NF as the positive electrode. The Co0.85Se/NF//AC HSC device exhibited remarkable electrochemical performance, achieving a high energy density of 66.6 Wh kg⁻¹ at a power density of 849.3 W kg⁻¹. It also maintained excellent cycling stability over 10,000 charge-discharge cycles. These findings highlight the significant potential of Co0.85Se microsphere-like structures as high-performance electrode materials for hybrid supercapacitors, paving the way for developing efficient energy storage technologies.

Recovering electroactive materials from spent primary batteries and converting them into useful products is a crucial and interesting topic for solving many environmental issues. Therefore, in this present work, we recovered useful electroactive materials from spent zinc-carbon (Zn-C) primary cells and utilized them to develop lithium-ion supercapacitor electrodes. In this typical recycling process, the electroactive composite was recovered using a two-step process combining electrochemical exfoliation and sonochemical technique. The structure, morphology and composition of the electroactive composite were studied in detail to explore its feasible electrode properties. Furthermore, a supercapacitor was designed using the composite; it operated at a wide voltage window of 2.5 V in 1 M LiClO4/acetonitrile electrolyte and showed a maximum specific capacitance of 84 F g-1. Moreover, the supercapacitor exhibited a high specific energy of similar to 18.22 W h kg-1 with a maximum specific power of similar to 6387 W kg-1 and a stability of similar to 73% over 10 000 charge/discharge cycles at 1 A g-1. Besides, the fabricated supercapacitor demonstrated practical application potential and showed that the composite recycled from spent primary cells is viable for developing rechargeable energy storage devices.

A streamlined design for nanoarchitecture can substantially enhance the performance of battery-type electrodes, leading to advanced hybrid supercapacitors (HSCs) with improved redox properties. Metal-organic frameworks (MOFs) are promising for electrochemical...

Metal pyrophosphates compounds with high conductivity and excellent redox properties are promising electrode materials for sustainable energy storage. So, the binder-free 1D stacked 2D Na7V3(P2O7)(4) (NVPO) nanosheets were grown on a carbon fiber cloth (C) (NVPO@C) through a two-step hydrothermal process followed by phosphorization under controlled atmospheric conditions. The binder-free 350-NVPO@C electrode exhibits an emergent architecture of intertwined nanofibers stabilizing over 2D enlarged nanosheets, providing enhanced ion transport pathways, improved conductivity, and expanded electroactive areas to boost sodium ion storage efficiency. It achieves a maximum gravimetric capacitance of 362 F g(-1) (257 F cm(-3)) at 4 A g(-1) with an excellent rate capability of similar to 76 % in a 1 M NaClO4/acetonitrile. Theoretical calculations suggest that (P2O7)(4-) plays a vital role in enhancing structural stability, facilitating ion diffusion, modifying the electronic structure, and boosting the adsorption energy of Na+. A 350-NVPO@C-based symmetric device with a broad electrochemical voltage of 2 V, delivering a maximal gravimetric energy density of 39 Wh kg(-1) (25.5 Wh cm(-3)) at a minimal gravimetric power density of 2005 W kg(-1) (1311 W cm(-3)), while maintaining an excellent capacity retention of similar to 89 % over 10,000 consecutive GCDs at 5 A g(-1). These findings highlight NVPO@C nanosheets as highly efficient electrodes for next-generation energy storage.

Recent research has faced challenges in achieving high specific capacitance and cycle stability with carbon nanofibers (CNFs) as supercapacitor electrodes. This study employs calcination/activation techniques to modify the electrochemical and structural properties of electrospun sulfur/nitrogen (S, N)-enriched CNFs. Combining the electrospinning process with these methods produces CNFs with a high energy density, enhancing non-faradaic processes. The 3D interconnected morphology of S, N-enriched CNFs possesses an appropriate surface area of 104.1 m2/g at 77 K with the high porous nature. Due to the excellent synergistic effect of nitrogen and sulfur atoms, the as-prepared porous CNFs showed excellent electrochemical performance in a three-electrode assembly. Under a neutral medium, the symmetric two-electrode cell displayed an outstanding electrochemical performance with a specific capacitance of 186F/g, an energy density of 25.8 Wh kg-1 , a power density of 500 W kg-1 and excellent capacitance retention of 88.2 % over 3000 charge-discharge cycles. The findings strongly indicate that the as-prepared CNFs have the potential to advance significantly energy storage technology, surpassing other reported carbon materials.

Supercapacitors play a crucial role in electrical energy storage and conversion applications today due to their high power density and ability to integrate with various energy conversion devices. Many efforts have been made to address issues such as low energy density and finding efficient electrode materials to achieve high capacitances. Layered transition metal dichalcogenides have shown great potential in energy storage applications because of their numerous active edges, diverse electrochemical kinetics, and unique sandwich structure. Therefore, researchers have been exploring a meticulous method to formulate multiscale CoS 2 , CoSe 2 , and CoTe 2 nanoarchitectures to enhance the storage characteristics of supercapacitors. This study employed a single‐step facile chemical reaction method to form CoSe 2 , CoTe 2 , and CoS 2 nanostructures. The synthesized CoTe 2 material demonstrated a specific capacity of 370 C g −1 at 1 A g −1 alongside reliable cycling robustness over 10,000 cycles (98%), superior to CoSe 2 and CoS 2 electrodes. An alkaline hybrid asymmetric supercapacitor based on CoTe 2 achieved a 157 F g −1 specific capacitance with 56 Wh kg −1 specific energy and a long cycling life of 97% capacitance retaining over 10,000 cycles. These findings reveal the significant potential of cobalt chalcogenide nanostructures to be applied as prototype electrodes for supercapacitor devices.

Co(OH)2 layers were grown on nickel foam by an instantaneous nucleation mechanism regulated by cathodic electrodeposition. Treating Co(OH)2 layers as the template, Ni(OH)2 layers were cladded onto to form Co(OH)2/ Ni(OH)2 heterojunction. The resultant self-supported binder-free architectures with abundant active sites and reduced aggregation facilitate faradaic redox reactions and shorten electron transport distance. The heterointerface-engineered Co(OH)2/Ni(OH)2 architecture with interfacial electronic coupling as electrodes highlighted its merits by delivering an areal capacity of 1965 mC cm- 2 at 1 mA cm- 2, a high specific capacity of 444 C g- 1, and a specific capacitance of 889 F g- 1 at 1 A g- 1. Moreover, the electrode demonstrated its chemical stability and structural endurance, with an 89.5 % retention of specific capacity at the 5000 th cycle. Additionally, the hybrid device assembled with Co(OH)2/Ni(OH)2//activated carbon composition delivered a specific capacity of 181 C g- 1 at 1 A g- 1, a maximum specific energy of 53.1 Wh kg- 1 at 1 A g- 1, and an appreciable specific power of 16.56 kW kg- 1 at 20 A g- 1. The proposed strategy takes advantage of yielding replicated twodimensional sheets (2D) with interfacial electronic coupling, ample active sites, and high synergy between the two layers, which help in designing high-energy electrochemical storage devices.

Engineering hybrid nanoarchitecture materials, which feature meticulously designed hierarchical frameworks and components, represents a highly effective approach to meeting the demanding performance requirements of supercapacitors (SCs). Herein, we present a simple and affordable anion exchange strategy to tailor a unique, multifaceted transition metal chalcogenide of MoS2 integrated with Co9S8 (CMS) nanohybrid hierarchical framework grown on a porous Ni-foam substrate, serving as a free-standing electrode for SC. It examines the effect of anion exchange processes on electrochemical performance, demonstrating significant enhancements in various metrics. The CMS nanohybrid material exhibits a hierarchical architecture along with outstanding intrinsic conductivity, which collectively enhances its electrochemical performance and ion/charge transfer efficiency. This improvement is attributed to the synergistic effects of the component, which facilitate more efficient electrochemical reactions and mitigate the volume expansion associated with charging and discharging. Interestingly, the CMS nanohybrid electrode exhibits an impressive specific capacitance of similar to 1325 F g(-1) at a current density of 1 A g(-1), along with a substantial rate capability of similar to 63.6 % at 20 A/g, significantly surpassing those of their hybrid metal oxide counterparts. Additionally, the hybrid supercapacitor comprising CMS and activated carbon achieved a specific capacitance of similar to 246 F g(-1) at a current density of 1 A g(-1), a maximum energy density of similar to 76.73 Wh kg(-1), and a power density of similar to 19.06 kW kg(-1), while maintaining similar to 91.7 % cycling stability after 12,000 cycles. Thus, this work could provide a framework for integrating advanced bimetallic chalcogenides to enhance energy storage performance.

Exploring highly electroactive electrode materials with compatible nanostructures, tunable properties, and strong conductive networks is vital for supercapacitors (SCs). However, comprehending this complex area remains a significant challenge. In this work, we report the synthesis of a hierarchical NiCo2O4@NiMoO4 (NCO@NMO) hybrid nanoarchitecture utilizing a cost-effective hydrothermal approach and subsequent annealing. This is achieved through facile and scalable in situ fabrication techniques that yield an electrode material suitable for advanced high-energy hybrid supercapacitors (HSCs). The unique hybrid nanoarchitecture is engineered to provide an effective, open-porous framework that facilitates ion diffusion and enables rapid electron transport. The NCO@NMO hybrid nanoarchitecture electrode exhibits a battery-type redox mechanism, achieving a peak specific capacitance of 1984 F g-1 at a current density of 1 A g-1 in an aqueous electrolyte, surpassing the performance of its individual components. Enhanced electrochemical performance is achieved by increasing the density of electroactive sites and conductivity through surface modifications, thereby facilitating rapid redox kinetics. Notably, the fabricated HSC device, with a configuration of NCO@NMO//activated carbon, demonstrates an impressive power density of 42.56 kW kg-1, complemented by an energy density of 75.04 Wh kg-1, and exhibits excellent cyclic stability, retaining up to 89.62 +/- 1.19 % of its capacitance, even after 20,000 cycles. The high energy density and considerable cyclic stability are comparatively higher than those of conventional SCs and even approach the values of commercial batteries.

The synergistic interaction and strategic manipulation of electronic structures by incorporating metal ions into the host matrix have captivated research efforts for supercapacitors. This study presents an efficient strategy for synthesizing Cu‐ion‐incorporated NiCo2O4 (CNCO) nano/microarchitectures using a hydrothermal method followed by heat treatment. It establishes a clear link between variations in Cu content and their effects on material properties, which influence electrochemical performance. Optimizing the Cu content enhances ion transport and conductivity, while creating active sites for faster charge transfer. The porous framework boosts structural integrity and mass transport, reducing aggregation risks. Enhanced performance stems from synergistic interactions between Cu and the NCO matrix in the CNCO nano/microarchitecture. The experimental findings are further substantiated by computational analyses utilizing density functional theory (DFT) calculations. Impressively, the regulated CNCO electrode material exhibits a remarkable specific capacitance of 1301 F/g at 1 A/g and a rate capability of 81.3% at 20 A/g, significantly outperforming other CNCO variants. The optimized CNCO electrode material contributes to a high‐performance battery‐supercapacitor hybrid system, achieving an energy density of 61.36 Wh/kg at a power density of 1.18 kW/kg, with excellent cyclic stability. This system illuminates green and pink light‐emitting diodes.

Recovering electroactive materials from the waste primary batteries and converting them into useful applications is a crucial and interesting topic for solving many environmental issues. Considering this account, in this...

This article introduces an innovative approach to tailor the morphology of boron carbide (B4C) particles by adjusting the polyols in polymeric precursors. This modification enables the control of the C/B2O3 ratio of the precursor and the formation of H3BO3 crystals on its surface. These H3BO3 crystals play a crucial role in inducing the growth of nano boron carbide particles with a high aspect ratio. Scanning electron microscopy (SEM) images depict that precursors lacking the ethylene glycol component yield polyhedral-equiaxed B4C particles. Conversely, the use of precursors containing 50 mol% ethylene glycol and the lowest C/B2O3 ratio leads to the formation of B4C particles with a needle-like morphology. Moreover, the influence of particle morphology on the electrochemical properties of boron carbide was investigated, and the potential of boron carbide in energy storage devices was delved into, with the needle-like boron carbide particles showed superior performance a specific capacitance of 139.7 F/g at 1 A/g and also showcased a long-term stability of 66 % after 5000 cycles.

Strategic design and synergistic interactions between the electrodes and electroactive materials profoundly influence the energy storage efficiency of supercapacitor devices. Herein, we present the interfacial engineering of CoMoS4-NiS2 with a well-defined construction of amorphous/crystalline heterophases deposited on carbon cloth using a hydrothermal technique. The optimal in-situ growth of CoMoS4- NiS2 @CFC boasts an impressive areal capacity of 1341 mC cm-2 and retains similar to 91 % capacity after 50 0 0 cycles, attributed to the synergy effect and improved conductivity of multi-metallic sulfide ions over the CFC substrate. Density functional theory (DFT) reveals the metallic nature of CoMoS4-NiS2 @CFC and favorable OH- ion adsorption energy of -4.35 eV, enhancing its charge storage capabilities. Furthermore, a hybrid supercapacitor (HSC) and Pouch HSC are assembled utilizing the CoMoS4-NiS2 @CFC as a positrode and marine waste jellyfish-derived AC as a negatrode with an aqueous electrolyte. The HSC and PHSC demonstrate superior specific energies of 51.99 and 58.4 W h kg-1, respectively, along with corresponding specific powers of 800 and 780 W kg-1, maintaining robust stability of similar to 90 % stability over 10 0 0 0 cycles. Additionally, the HSC and PHSC have successfully illuminated several light-emitting diodes (LEDs) demonstrating superior energy storage performance. This work advances the design of hetero-phase multi-metal sulfides, paving the way for high-performance supercapacitor devices. (c) 2025 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Cobalt metal-organic frameworks were used as templates to obtain densely stacked two-dimensional ultrathin nanosheets of nickel/cobalt metal-organic frameworks on carbon cloth via in situ deposition at room temperature. The freestanding electrodes made of ultra-thin nanosheets and quasi-one-dimensional pores exhibited a unique electronic structure with Ni(OH)(2) anchored to the surface. With distinctive structural superiority, multiple charge transfer routes, and Ni(OH)(2) moieties as active sites, the electrode showcased a high areal capacity (C-a) of 2041 mC cm(-2) (2 mA cm(-2)), a specific capacity of (C-s) 671 C g(-1), a volumetric capacitance (C-vc) of 1033 F cm(-3) (2 A g(-1)) and a prolonged cycling life of 5000 cycles with an appreciable capacity retention of 91.5% in 6 M KOH. The asymmetric supercapacitor device assembled (CC/CoNi-MOF@Ni(OH)(2)//CC/O,N,S@AC) delivered a superior specific capacity (C-s) of 284 C g(-1), a specific capacitance (C-sp) of 189 F g(-1), a volumetric capacitance (C-vc) of 128 F cm(-3), a maximum specific energy (E-s) of 75.0 W h kg(-1), and an excellent specific power (P-s) of 17.13 kW kg(-1), and withstood 10 000 charge/discharge cycles with a decline of 11.3% in the initial capacity. The proposed method with DFT analysis underpins a strategy to custom-design economically viable freestanding electrodes with a large surface area per volume/mass, a synergy effect at the interface, and multiple charge transfer pathways for potential application in energy storage.

Nickel foam-supported binder-free cobalt manganese selenide (CoMnSe@NF) was grown by in situ deposition using metal organic frameworks (MOFs) as the template with metal node engineering. The CoMnSe@NF electrode employed as the positive electrode for supercapacitors delivered well-pronounced conductivity, a high areal capacity (C-a) of 1714 mC cm(-2) at 1 mA cm(-2), and a specific capacity (C-s) of 519 C g(1-) (1 A g(-1)) withstanding over 5000 cycles with a good retention of 87% of its initial capacity. The outstanding electrochemical profile of CoMnSe@NF can be credited to the tailor-made synergetic surface, bearing densely packed 2-dimensional sheets harboring numerous redox sites with an even distribution of voids, allowing easy passageway and diffusion of the electrolyte. Armed with the said caliber of CoMnSe@NF, the asymmetric device fabricated (CoMnSe@NF-2h//O, N, S@AC@NF) delivered a remarkable specific capacity (C-s) of 139 C g(-1), maximum energy density (E-s) of 35.47 W h kg(-1), and a power density of 11,500 W kg(-1), remaining intact beyond 10,000 charge-discharge cycles and retaining 82.6% of the initial capacity.

This paper reports the successful synthesis of a novel core/shell structure featuring cobalt selenide nanowires coated with nickel-cobalt layered double hydroxide (Co0.85Se@NiCo-LDH). Co0.85Se nanowires were encapsulated within NiCo-LDH nanosheets on a nickel foam (NF) substrate using a facile three-step synthesis method. Initially, core cobalt carbonate hydroxide hydrate nanowires (CCHH) were grown on an NF substrate using a hydrothermal approach. The Co0.85Se nanowires were then obtained using a selenization process. Finally, a NiCo-LDH nanosheet shell was deposited via an electrodeposition method. The resulting Co0.85Se@NiCo-LDH material exhibited a remarkable specific capacity of 1314C g- 1 at 1.0 A g- 1 owing to its unique core/shell architecture and composition, demonstrating exceptional rate capability with a performance retention of 61.5 % even at a high current density of 20 A g-1. Moreover, it displayed remarkable cycling stability, retaining 89.2 % of its initial capacity after 10,000 cycles. A hybrid supercapacitor device was constructed using Co0.85Se@NiCoLDH as the positive electrode and activated carbon as the negative electrode. This configuration yielded an impressive energy density of 72.2 Wh kg- 1 and a high-power density of 849.9 W kg-1, while maintaining excellent cycling stability with 88.2 % retention after 10,000 cycles. These findings highlight the potential of core/shell architectures for developing high-performance supercapacitors with improved kinetics and stability.

Potassium birnessite is a remarkable material with a wider inter-planar spacing, which enables to accommodate more electrolytic ions to improve overall electrochemical performances. In this work, controlled synthesis of K(0.46)Mn(2)O4(H2O)(1.4) (HKMO) nanosheets were interconnected mesoporous networks uniformly grown on carbon cloth (CC) via a one-step hydrothermal process. Specifically, the HKMO sample synthesized at 100 degrees C for 12 h (100@HKMO-12 h) exhibited a mesoporous morphology with a large specific surface area. The binder-free 100@HKMO-12 h electrode exhibits a maximum specific capacitance of 255F g(-1) (323F cm(-3)) in 1 M NaClO4/acetonitrile electrolyte over a broad potential range of 3 V. DFT studies demonstrated the interlayer distance increased by the insertion of K+ ions into the MnO2 matrix. Bader charge analysis showed a 12.09 |e| charge difference for K-birnessite in the inter-layer region compared to the normal birnessite, supported the increase of inter-layer region in the MnO2 matrix. Significantly, the increased interlayer the distance, promoted rapid intercalation/deintercalation of Na+ ions and allowed the reversible faradic pseudocapacitance reaction to occur at a wider potential window. Moreover, the symmetric full-cell fabricated utilizing the 100@HKMO-12 h electrodes have a wide voltage of 2 V and the device delivered a maximum specific energy of 43 Wh kg(-1) (28 Wh cm(-3)) at a minimum specific power of 556 W Kg(-1) (349 W cm(-3)). Besides, the device showed an excellent capacitance retention of similar to 94 % even after 10,000 continuous charge-discharge cycles at a current of 5 A/g, indicating it is a potential candidate for next-generation sodium energy storage devices.

The growing demand for sustainable energy sources has led to a change in attention towards developing costeffective, high-performance energy storage devices. The construction of porous carbon network nanostructures with high surface area is complex for current-generation supercapacitors, mainly due to molecular flexibility and carbon production constraints. This work successfully produced a porous carbon nanostructure by doping phosphorous into nitrogen-based carbon nanofibers (P-doped NCNFs) utilizing a simple and controllable approach. This process entailed electrospinning diammonium hydrogen phosphate and polyacrylonitrile, subsequent high-temperature carbonization, and substantial segmented hydrogen peroxide activation processes. The P-doped NCNFs had a notable surface area of 100.69 m2 g-1, characterized by a distinct 3D-interconnected weaving network morphology. The 1 % P-doped NCNFs exhibited an exceptionally high capacitance of 265 +/- 2 F g-1 when tested in a three-electrode setup at a current density of 0.5 A g-1. In addition, the constructed symmetrical supercapacitors with two identical P-doped NCNFs using a neutral Na2SO4 electrolyte exhibited remarkable electrochemical characteristics, which include a substantial capacitance of 225 +/- 2 F g-1 at a current density of 0.5 A g-1, a high energy density of 30.9 Wh kg-1, an excellent Coulombic efficiency of 98.8 % over 6000 cycles, an impressive power density of 250 W kg-1, and significant capacitance retention of 85.6 %. These findings suggest that P-doped NCNFs could be excellent options for next-generation high-performance supercapacitors.