The inertness of Ce(iii/iv), a lanthanide with localized electrons, hampers its practical application in energy storage. Considering the inertness of Ce, it is necessary to identify the fatal bottlenecks and carry out challenging transformations that can influence electrochemical performance. The fabrication of a heterostructure by combining a transition metal (Ni) and a lanthanide (Ce) via a bottom-up approach can mitigate the inertness of the latter. Herein, we outline a distinct electronic modulation strategy to enhance the internal electronic interaction between Ce and Ni via Ni 3d-O 2p-Ce 4f orbital coupling, and the resulting electron delocalization is accompanied by migrant oxygen vacancies. The interfacial restructuring of the Ni- and Ce-based heterostructure outperformed its Ce-based counterpart, with enhanced electrochemical performance. The deep insight drawn from this paradigm shift unfolds a wide scope in employing transition metals to enhance the lanthanides with expanded functionalities for impressive advancements in energy technologies.

The advancement of high-performance electrocatalysts for the hydrogen evolution reaction and oxygen evolution reaction (HER and OER) is essential for the progress of sustainable energy technologies. In this work, biomass-derived carbon quantum dots (CQDs) from Azadirachta indica were incorporated into AlSi10Mg alloy via a hydrothermal method to improve electrocatalytic activity. X-ray diffraction (XRD) confirmed the crystalline nature of both AlSi10Mg and AlSi10Mg@CQD, while Raman spectroscopy indicated the retention of silicon phonon modes and the presence of D and G bands, confirming the successful incorporation of CQDs within the alloy matrix. Field-emission scanning electron microscopy (FESEM) and elemental mapping revealed the morphology and distribution of CQDs on the AlSi10Mg surface, which was further validated by high-resolution transmission electron microscopy (HRTEM).X-ray photoelectron spectroscopy (XPS) confirmed the surface elemental composition and chemical oxidation states of the constituent elements. The AlSi10Mg exhibited an electrochemically active surface area (ECSA) from 0.162 to 3.27 m2/g, after the incorporation of CQDs indicating a higher density of accessible active sites. Electrochemical measurements revealed that the AlSi10Mg@CQD electrocatalyst exhibited a low overpotential of 155 mV at 10 mA/cm2, reflecting enhanced catalytic activity and charge-transfer kinetics towards HER. Notably, after prolonged stability testing, the overpotential further decreased to 120 mV, demonstrating superior catalytic activation and excellent operational stability during HER performance. These results highlight the potential of CQD-functionalized AlSi10Mg as a promising HER catalyst for water-splitting applications.

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.

Ternary transition metal oxides (TTMOs) have emerged as a new class of electrode materials for high-performance energy storage systems, particularly supercapacitors (SCs) and hybrid battery-capacitor devices. This comprehensive review aims to comprehensively survey recent advances in the design, synthesis, and analysis of TTMOs-based nanostructures for supercapacitor (SC) electrodes. It begins by outlining the key concepts related to charge storage mechanisms in SC electrodes, electric double-layer capacitance (EDL), pseudocapacitive (PC), and battery-type (BT) behavior, followed by a clarification of device configurations, including symmetric (SSC), asymmetric (ASC), and hybrid supercapacitors (HSC) devices. This review then examines the fabrication strategies for TTMOs, emphasizing the impact of synthetic approaches on material morphology, crystallinity, and electrochemical performance. Special attention is given to the structure-property relationships that govern ion transport and charge storage dynamics in these materials. The influence of morphological features, including dimensionality, porosity, and hierarchical architecture, on electrochemical behavior is critically analyzed. A comparative evaluation of electrochemical matrices across various TTMO electrodes is presented, highlighting key performance benchmarks and challenges. Ultimately, the review highlights emerging trends, current limitations, and future research directions that are poised to accelerate the development of next-generation TTMO materials for advanced energy storage technologies.

The development of battery-type supercapacitor electrodes faces significant challenges due to poor rate capability and cyclic stability, largely caused by sluggish reaction kinetics. In this study, we report a unique 2D CeO2/ Co3O4 heterostructure designed to enhance energy storage performance in aqueous hybrid systems. By investigating the interplay between cubic Ce-O and octahedral Co-O species, we reveal that distortion-driven electron delocalization and gradient orbital hybridization serve as critical mechanisms for improving charge storage kinetics. Our findings, supported by both experimental data and theoretical calculations, highlight that the distorted geometry at the Co-O-Ce boundary facilitates effective electronic interaction and activates inert 4f states. As a result, the CeO2/Co3O4 heterostructure-based hybrid capacitor achieves an exceptional specific energy (Es) of 57.94 Wh kg-1 at a specific power (Ps) of 1.178 kW kg-1, with an impressive capacity retention of 81.5 % over 10,000 cycles. Notably, it retains an Es of 51.25 Wh kg-1 even at a high Ps of 13.17 kW kg-1, showcasing remarkable charge storage kinetics. This work contributes significantly to the electronic modulation strategies for supercapacitor electrodes, leveraging geometrical distortion and d-f orbital hybridization for enhanced performance.

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.

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.

Ternary transition metal oxides (TTMOs) have emerged as a new class of electrode materials for high-performance energy storage systems, particularly supercapacitors (SCs) and hybrid battery-capacitor devices. This comprehensive review aims to comprehensively survey recent advances in the design, synthesis, and analysis of TTMOs-based nanostructures for SC electrodes. It begins by outlining the key concepts related to charge storage mechanisms in SC electrodes, electric double-layer (EDL) capacitance, pseudocapacitive (PC), and battery-type (BT) behavior, followed by a clarification of device configurations, including symmetric SC (SSC), asymmetric SC (ASC), and hybrid SC (HSC) devices. This review then examines the fabrication strategies for TTMOs, emphasizing the impact of synthetic approaches on material morphology, crystallinity, and electrochemical performance. Special attention is given to the structure-property relationships that govern ion transport and charge storage dynamics in these materials. The influence of morphological features, including dimensionality, porosity, and hierarchical architecture, on electrochemical behavior is critically analyzed. A comparative evaluation of electrochemical matrices across various TTMO electrodes is presented, highlighting key performance and challenges. Ultimately, the review highlights emerging trends, current limitations, and future research directions that are poised to accelerate the development of next-generation TTMO materials for advanced energy storage technologies.

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...

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.

Electrode materials with fascinating nanostructures and enhanced charge storage capabilities have become an area of significant research interest, as they can enable the electrochemical properties in advanced energy storage devices. In this study, Co3(PO4)2⋅8H2O (CP), Ni3(PO4)2⋅8H2O (NP), and (Ni-Co)3(PO4)2⋅8H2O (NCP) were synthesized using a polyol-based reflux method, without any unique atmosphere or post-heat treatment. The synthesized materials were analyzed for their structural and morphological properties. During the electrochemical study, the synthesized electrode materials showed pseudocapacitive properties. The electrochemical performance of the NCP electrode material was evaluated in a three-electrode system using a 1 M KOH solution, revealing a maximum specific capacity of around 713.33 Fg−1 at a specific current of 1 Ag−1. Subsequently the NCP material was utilized as the electrode in a device paired with charcoal activated carbon (AC) as the negative electrode. This setup maintained an enduring capacity of 144.66 Fg−1 at a density of 1 Ag−1, along with specific energy and power levels of45.20 WhKg−1 and 749.96 W Kg−1 respectively. After more than 10,000 cycles, the device proved to have a coulombic efficiency of 98

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.