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In recent years, paper‐based functional materials have received extensive attention in the field of energy storage due to their advantages of rich and adjustable porous network structure and good flexibility. As an important energy storage device, paper‐based supercapacitors have important application prospects in many fields and have also received extensive attention from researchers in recent years. At present, researchers have modified and regulated paper‐based materials by different means such as structural design and material composition to enhance their electrochemical storage capacity. The development of paper‐based supercapacitors provides an important direction for the development of green and sustainable energy. Therefore, it is of great significance to summarize the relevant work of paper‐based supercapacitors for their rapid development and application. In this review, the recent research progress of paper‐based supercapacitors based on cellulose was summarized in terms of various cellulose‐based composites, preparation skills, and electrochemical performance. Finally, some opinions on the problems in the development of this field and the future development trend were proposed. It is hoped that this review can provide valuable references and ideas for the rapid development of paper‐based energy storage devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • Bilayered V 2 O 5 nH 2 O xerogel constructed 2D nanopapers were synthesized. • The V 2 O 5 nH 2 O Xerogel combines oxygen defect engineering. • Oxygen defect improves Zn2+/Mg2+ insertion/extraction kinetics. Aqueous zinc ion batteries (AZIBs) and aqueous magnesium ion batteries (AMIBs) offer powerful alternatives for large-scale energy storage because of their high safety and low cost. Consequently, the design of high-performance cathode materials is essential. In this paper, we present a simple strategy that combines oxygen defect (O d) engineering with a 2D-on-2D homogeneous nanopape-like bilayer V 2 O 5 nH 2 O xerogel (BL-HVO d NPS). This strategy employs O d to improve Zn2+/Mg2+insertion/extraction kinetics and reduce irreversible processes for high-performance AZIBs/AMIBs. And interlayer water molecules serve as an effective spacer to stabilize the expanded interlayer gap in BL-HVO d NPS, thereby providing extended diffusion channels for Zn2+/Mg2+ during insertion/extraction. The interlayer water molecules help shield the electrostatic interaction between Zn2+/Mg2+ and BL-HVO d NPS lattice, which improves diffusion kinetics during repeated. In addition, electrochemical characterization results indicate that the BL-HVO d NPS can effectively the surface adsorption and internal diffusion of Zn2+/Mg2+. More importantly, the successfully prepared unique 2D-on-2D homogenous nanopaper structure enhances electrolyte/electrode contact and reduces the migration/diffusion path of electrons/Zn2+ and Mg2+, thus greatly improving rate performance. As a result, the BL-HVO d NPS as AZIBs/AMIBs electrodes offer better reversible capacity of 361.8 and 162.8 mA h g−1 (at 0.2 A g−1), while displaying impressively long cycle lifes. This method provides a way to prepare advanced xerogel cathode materials for AZIBs and AMIBs. [ABSTRACT FROM AUTHOR]

Abstract An efficient method that utilizes simple techniques, easy operation, and low‐cost production to create flexible graphene‐based materials is a worthy practical challenge. A rapid strategy for preparing flexible, functional graphene oxide (GO) is introduced using GO‐ethanol dispersion filtration. The filtration process is highly efficient and drying time is significantly reduced by employing ethanol as solvent, due to the fact that ethanol is a volatile liquid. Freestanding GO papers can be harvested with ultralarge size (700 cm2), color variety, and writable characteristics. After reduction, N‐doped graphene (NDG) papers still maintain good foldability with improved electric conductivity and porous structure. When used as an electrode for a supercapacitor, the flexible NDG paper device demonstrates good electrochemical performance even with size expansion and extreme double folding. Moreover, this NDG paper capacitor device shows a good electrosorption performance for capacitive deionization of sulfate and chromate in groundwater system. These flexible GO and NDG papers promise potential to facilitate the production of graphene‐based materials for practical applications in energy and environmental related fields.

The MXene-modified papers with high-uniform loading of polypyrrole and excellent conductivity have been fabricated via a multiple self-assembly and in-situ polymerization strategy, which achieves boosting areal capacitance. [Display omitted] • Multiple self-assembly and in-situ polymerization strategy is proposed tofabricate paper-based supercapacitors. • Alternate adsorption of MXene and polypyrrole on paper yields an ultra-high polypyrrole loading of 10.0 mg/cm2. • The paper-based supercapacitor shows a boosting areal capacitance of 2316 mF/cm2. Despite the intriguing features of freestanding flexible electronic devices, such as their binder-free nature and cost-effectiveness, the limited loading capacity of active material poses a challenge to achieving practical high-performance flexible electrodes. We propose a novel approach that integrates multiple self-assembly and in-situ polymerization techniques to fabricate a high-loading paper-based flexible electrode (MXene/Polypyrrole/Paper) with exceptional areal capacitance. The approach enables polypyrrole to form a porous conductive network structure on the surface of paper fiber through MXene grafting via hydrogen bonding and electrostatic interaction, resulting in an exceptionally high polypyrrole loading of 10.0 mg/cm2 and a conductivity of 2.03 S/cm. Moreover, MXene-modified polypyrrole paper exhibits a more homogeneous pore size distribution ranging from 5 to 50 μm and an increased specific surface area of 3.11 m2/g. Additionally, we have optimized in-situ polymerization cycles for paper-based supercapacitors, resulting in a remarkable areal capacitance of 2316 mF/cm2 (at 2 mA/cm2). The capacitance retention rate and conductivity rate maintain over 90 % after undergoing 100 bends.The maximum energy density and cycling stability are characterized to be 83.6 μWh/cm2 and up to 96 % retention after 10,000 cycles. These results significantly outperform those previously reported for paper-based counterparts. Overall, our work presents a facile and versatile strategy for assembling high-loading, paper-based flexible supercapacitors network architecture that can be employed in developing large-scale energy storage devices. [ABSTRACT FROM AUTHOR]

Energy storage devices (ESD) which are intended to power electronic devices, used in close contact of human skin, are desirable to be safe and non-toxic. In light of this requirement, Zn based energy storage devices seem to provide a viable pathway as they mostly employ aqueous based electrolytes which are safe and non-toxic in their functioning. Additionally, having a flexible ESD will play a crucial role as it will enable the ESD to conform to the varying shapes and sizes of wearable electronics which they energize. In this work, we have developed an inkjet-printed Zinc ion battery (IPZIB) with planar electrode configuration over bond paper substrate. Zn has been used as the negative electrode, MnO2 is used as the positive electrode with Poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) as the active binder. Conducting tracks of reduced graphene oxide (rGO) are used to construct the current collector on the paper substrate. The fabricated IPZIB delivered a high discharge capacity of 300.14 mAh g−1 at a current density of 200 mA g−1. The energy density of the IPZIB is observed as 330.15 Wh kg−1 at a power density of 220 W kg−1 and retains an energy density of 94.36 Wh kg−1 at a high power density of 1650 W kg−1. Finally, we have demonstrated the capability of the IPZIB to power a LED at various bending and folding conditions which indicates its potential to be used in the next generation flexible and wearable electronic devices. [ABSTRACT FROM AUTHOR]

Efficient and sustainable energy storage remains a critical challenge in the advancement of energy technologies. This study presents the fabrication and electrochemical evaluation of a self-supporting electrode material composed of MnO2 nanorods grown directly on a carbon paper and carbon nanotube (CNT) substrate using a hydrothermal method. The resulting CNT/MnO2 electrodes exhibit a unique structural architecture with a high surface area and a three-dimensional hierarchical arrangement, contributing to a substantial electrochemical surface area. Electrochemical testing reveals remarkable performance characteristics, including a specific capacitance of up to 316.5 F/g, which is 11 times greater than that of conventional CP/MnO2 electrodes. Moreover, the CNT/MnO2 electrodes demonstrate outstanding retention capacity, exhibiting a remarkable 165% increase over 10,000 cycles. Symmetric supercapacitor devices utilizing CNT/MnO2 electrodes maintain a large voltage window of 3 V and a specific capacitance as high as 200 F/g. These results underscore the potential of free-standing CNT/MnO2 electrodes to advance the development of high-performance supercapacitors, which can be crucial for efficient and sustainable energy storage solutions in various industrial and manufacturing applications. [ABSTRACT FROM AUTHOR]

The reuse of waste papers by conversion into valuable carbon materials has received considerable attention for diverse applications such as energy storage and water purification. However, traditional methods for converting waste papers into materials with suitable properties for specific applications are often complex and ineffective, involving consecutive carbonization and activation steps. Herein, we propose a simple one-step microwave (MW)-assisted synthesis for preparing waste paper-derived porous carbons (WPCs) for energy storage and water purification. Through a 30-min synthesis, WPCs with graphitic structure and high specific surface area were successfully produced. The fabricated WPCs exhibited outstanding charge storage capability with a maximum specific capacitance of 237.7 F g−1. Additionally, the WPC demonstrates a high removal efficiency for various dyes, achieving a maximum removal efficiency of 95.0% for methylene blue. The developed one-step MW synthesis not only enables the production of porous carbon from waste paper, but also offers a viable approach to address solid waste management challenges while simultaneously yielding valuable materials. [Display omitted] • Waste paper-derived porous carbons were synthesized by one-step microwave synthesis. • Within 30-min MW synthesis, graphitic and high-surface area WPCs were produced. • WPC exhibits outstanding electrochemical capacitance of 237.7 F g−1. • WPC exhibits high removal of various dyes, with maximum of 95.0% for methylene blue. [ABSTRACT FROM AUTHOR]

Sodium‐carbon dioxide (Na‐CO2) batteries are regarded as promising energy storage technologies because of their impressive theoretical energy density and CO2 reutilization, but their practical applications are restricted by uncontrollable sodium dendrite growth and poor electrochemical kinetics of CO2 cathode. Constructing suitable multifunctional electrodes for dendrite‐free anodes and kinetics‐enhanced CO2 cathodes is considered one of the most important ways to advance the practical application of Na‐CO2 batteries. Herein, RuO2 nanoparticles encapsulated in carbon paper (RuCP) are rationally designed and employed as both Na anode host and CO2 cathode in Na‐CO2 batteries. The outstanding sodiophilicity and high catalytic activity of RuCP electrodes can simultaneously contribute to homogenous Na+ distribution and dendrite‐free sodium structure at the anode, as well as strengthen discharge and charge kinetics at the cathode. The morphological evolution confirmed the uniform deposition of Na on RuCP anode with dense and flat interfaces, delivering enhanced Coulombic efficiency of 99.5% and cycling stability near 1500 cycles. Meanwhile, Na‐CO2 batteries with RuCP cathode demonstrated excellent cycling stability (>350 cycles). Significantly, implementation of a dendrite‐free RuCP@Na anode and catalytic‐site‐rich RuCP cathode allowed for the construction of a symmetric Na‐CO2 battery with long‐duration cyclability, offering inspiration for extensive practical uses of Na‐CO2 batteries. [ABSTRACT FROM AUTHOR]

A test bed with a coplanar architecture is employed to investigate the integration of an in situ cross-linked, polymer-supported ionogel with several commercially available, high surface area carbon paper electrodes. Specifically, a UV-cured poly(ethylene glycol) diacrylate (PEGDA)-supported ionogel electrolyte film is formed in situ against a variety of porous electrodes comprising: a carbon fiber paper, a carbon aerogel paper, and four carbon nanotube-based papers. Electrochemical impedance spectroscopy measurements reveal that the relative performance of a particular carbon paper with the neat ionic liquid is not necessarily indicative of its behavior when integrated with the solid ionogel electrolyte. The coplanar test bed can therefore serve as a useful tool to help guide the selection of suitable carbon-based electrode structures for supercapacitors that incorporate UV-cured ionogels created in situ for wearable energy storage applications.

• Three-dimensional WO 2 /MoO 2 @P, N-CNTs were prepared by the Self-template method. • Highly conductive and hollow structure of WO 2 /MoO 2 @P, N-CNTs avoided aggregation of NiCo-LDH. • IMSC devices were prepared by fully screen-printed technology. • IMSCs demonstrated excellent energy density (0.0590 mWh cm−2), cycling stability (100% capacity retention after 10,000 cycles) and mechanical stability (lighting the bulb under extremely distorted conditions). In-plane micro-supercapacitors (IMSCs) have greater promise for use in flexible wearable electronics than traditional stacked configurations due to their ease of integration and conformability. Nickel-cobalt layered double hydroxide (NiCo-LDH) has garnered significant interest as a stellar material for supercapacitors because of its affordable price, regular morphology, and high theoretical capacity. Unfortunately, the intrinsic poor conductivity of LDH materials prevents supercapacitors from achieving long-term stable cycling and the desired energy density. This research successfully applies the self-templated approach to prepare carbon nanotubes (CNTs) with heterogeneous architectures and numerous phase interfaces, thereby mitigating this disadvantage. Carbon nanosheets adorned with WO 2 and MoO 2 nanoparticles assemble the CNT with a typical three-dimensional structure. When combined with LDH in a suitable ratio, the composite electrode's conductivity significantly improves, providing increased capacity and cycling stability. Compared to commercial CNTs, the larger size of the prepared WO 2 /MoO 2 @P, N-CNTs serves a superior supporting and connecting role, thereby preventing the NiCo-LDH from aggregating. Under the best conditions, the composite electrode demonstrates a capacity of 1237 C/g at 1 A g−1 and an optimal capacity retention of more than 92%. For the IMSC devices, the composite materials as the positive electrode achieve an energy density of 0.0590 mWh cm−2, and no capacity degradation is observed after 10,000 cycles. In addition, bending tests have demonstrated the mechanical stability of the IMSCs. Therefore, this strategy of mixing highly conductive WO 2 /MoO 2 @P, N-CNTs can effectively improve the conductivity of the composite material and the mechanical properties of the overall device. Furthermore, this concept can be further extended to the preparation and application of other wearable devices. [ABSTRACT FROM AUTHOR]

The large-scale implementation of renewable energy systems necessitates the development of energy storage solutions to effectively manage imbalances between energy supply and demand. Herein, we investigate such a scalable material solution for energy storage in supercapacitors constructed from readily available material precursors that can be locally sourced from virtually anywhere on the planet, namely cement, water, and carbon black. We characterize our carbon-cement electrodes by combining correlative EDS-Raman spectroscopy with capacitance measurements derived from cyclic voltammetry and galvanostatic charge-discharge experiments using integer and fractional derivatives to correct for rate and current intensity effects. Texture analysis reveals that the hydration reactions of cement in the presence of carbon generate a fractal-like electron-conducting carbon network that permeates the load-bearing cement-based matrix. The energy storage capacity of this space-filling carbon black network of the high specific surface area accessible to charge storage is shown to be an intensive quantity, whereas the high-rate capability of the carbon-cement electrodes exhibits self-similarity due to the hydration porosity available for charge transport. This intensive and self-similar nature of energy storage and rate capability represents an opportunity for mass scaling from electrode to structural scales. The availability, versatility, and scalability of these carbon-cement supercapacitors opens a horizon for the design of multifunctional structures that leverage high energy storage capacity, highrate charge/discharge capabilities, and structural strength for sustainable residential and industrial applications ranging from energy autarkic shelters and self-charging roads for electric vehicles, to intermittent energy storage for wind turbines and tidal power stations. [ABSTRACT FROM AUTHOR]

In an era of modern smart technology, flexible electrodes are of great interest for different energy conversion as well as energy storage applications like solar cells, all solid-state batteries, and supercapacitors. Flexible metal oxide-based paper electrodes are advantageous in comparison to conventional electrodes due to their economical synthesis, biocompatibility, and environment-friendly characteristics. However, the electrical conductivity of paper electrodes is limited because of the insulating nature of natural fibers employed as a binder for the flexible matrix of metal oxides. The current study is an attempt to tune the electrical properties of lignocelluloses (natural fibers) and titanium dioxide (TiO 2) based paper electrodes by facile electrodeposition technique. The crystalline parts (e.g., TiO 2 , Ag, and Au) of the prepared composite sheets were characterized by XRD analysis while the surface morphology was studied by SEM. FTIR was used to characterize the organic matter in LC fibers by identifying various molecular stretching and vibrational modes of C, H, and O-containing molecules. Electric permittivity was measured as a function of electric field frequency at room temperature which revealed the value of 23. 5 (at 1 kHz) for the sample LC/TiO 2 /Ag 9000s indicating the best charge storing capability of the sample. Impedance analysis was employed to identify various charge carrier mechanisms active in the sheets. It was found through impedance analysis that there is an active diffusion-controlled impedance mechanism of Au-coated samples causing an increased conductivity via the ionic diffusion. This diffusion-controlled conduction was modeled by the Warburg element. The enhanced conductivity due to ionic diffusion makes these samples more useful as electrodes. Cyclic voltammetry (CV) measurements of the electrodeposited samples established the increase in conductive properties and efficient kinetics of LC/TiO 2 paper sheets. The current study suggests that Ag and Au-coated paper electrodes can be potential candidates for energy conversion and storage applications. [ABSTRACT FROM AUTHOR]

Zinc–air batteries proffer high energy density and cyclic stability at low costs but lack disadvantages like sluggish reactions at the cathode and the formation of by-products at the cathode. To resolve these issues, a new perovskite material, CaCu3Ti4O12 (CCTO), is proposed as an efficacious electrocatalyst for oxygen evolution/reduction reactions to develop zinc–air batteries (ZAB). Synthesis of this material adopted an effective oxalate route, which led to the purity in the electrocatalyst composition. The CCTO material is a proven potential candidate for energy applications because of its high dielectric permittivity (ε) and occupies an improved ORR-OER activity with better onset potential, current density, and stability. The Tafel value for CCTO was obtained out to be 80 mV dec−1. The CCTO perovskite was also evaluated for the zinc–air battery as an air electrode, corresponding to the high specific capacitance of 801 mAh g−1 with the greater cyclic efficiency and minimum variations in both charge/discharge processes. The highest power density (Pmax) measured was 127 mW cm−2. Also, the CCTO based paper battery shows an excellent performance achieving a specific capacity of 614 mAh g−1. The obtained results promise CCTO as a potential and cheap electrocatalyst for energy applications. [ABSTRACT FROM AUTHOR]

Hierarchical composites (CFP–PANI) of carbon fiber papers (CFP) and polyaniline (PANI) have been facilely prepared by in-situ polymerization of aniline monomers on the surface of CFP films, which were simply obtained by low-cost carbonization of widely used filter paper. The wood–celluloses, which serve as the main component and the backbone of filter paper, are key raw materials for fabricating energy-related devices. Carbon fibers with porous structure were formed after the cellulose fibers were carbonized at high temperature. And cross-linked conductive networks have been achieved with the carbon fibers connected with each other. Different amounts of aniline monomer were in-situ polymerized on the surface of CFP, resulting in the formation of three-dimensional (3D) free-standing composite paper of CFP–PANI. Compared with pristine CFP and pure PANI, greatly enhanced electrochemical performance of CFP–PANI composite has been successfully achieved, including high specific capacitance (334 F g −1 ), good cycling stability as well as excellent rate capability. These superior electrochemical properties of CFP–PANI composite paper can be ascribed to the hierarchical structure of CFP, strong interaction between CFP and PANI, as well as the synergistic capacitance performance of CFP films and PANI nanoparticles, suggesting CFP–PANI composite paper thus simply prepared is good candidate for applications in high performance energy storage fields. [ABSTRACT FROM AUTHOR]

Polypyrrole@cellulose fibers (PPy@CFs) electrode materials are promising candidates in the energy storage. Various strategies have been pursued to improve their electrochemical performance. However, the poor conductivity, specific capacitance, and cyclic stability still hindered its application. Compared with the previous studies, we selected AQS with electrochemical activity as a dopant to improve these defects. It exhibits a high capacitance of 829.8 F g−1 at a current density of 0.2 A g−1, which is much higher than that of PPy@CFs electrode material (261.9 F g−1). Moreover, the capacitance retention of PPy:AQS/p-PTSA@CFs reaches up to 96.01% after 1000 cycles, indicating superior cyclic stability. Therefore, this work provides an efficient strategy for constructing high-performance electrode materials for energy storage. [ABSTRACT FROM AUTHOR]

Organic molecule stabilized manganese stannate (MnSnO 3) perovskite nanoparticles were synthesized using a complexion strategy route. The Rietveld refinement analysis confirmed the formation of orthorhombic structure of manganese stannate with the space group of Pnma. Free standing manganese stannate electrode was fabricated on paper based flexible substrate and investigated the electrochemical performances. The maximum specific capacitance and areal capacitance delivered by electrode were ∼ 183 F/g and ∼ 487 mF/cm2, respectively, at the current density of 0.2 A/g, with an excellent capacitance retention ∼ 93% for 103 cycles at 0.6 A/g. A symmetric supercapacitor was fabricated using the MnSnO 3 as active material on positive and negative electrodes in solid state gel electrolyte configuration. The device achieved the specific capacity value ∼ 156 mAh/g at 0.1 A/g with the energy density and power density of ∼ 10 Wh/kg and ∼ 22 kW/kg, respectively, at 0.5 A/g. These results suggested that manganese stannate nanoparticles are promising candidates for high-performance supercapacitor application. [Display omitted] • Organic molecule stabilized manganese stannate perovskite nanoparticles. • Flexible Au-coated paper based free-standing electrode and symmetric device were fabricated for supercapacitor applications. • Diffusive control mechanism dominated the overall charge storage process. • The fabricated device exhibited excellent stability for energy and power storage performance. [ABSTRACT FROM AUTHOR]

As one of the most promising energy-storage devices, supercapacitors have drawn great research interests because of their outstanding electrochemical behavior. Carbon paper holds great prospect as an electrode material for supercapacitors since it is inexpensive and highly conductive. In this paper, the modified Hummer's method is employed as an effective strategy to produce activated carbon paper with rougher surfaces and increased specific surface areas. It is further observed that hydrophilic groups such as hydroxyl (-OH), carbonyl (>C=O), and carboxyl (-COOH) have been introduced into the surface of carbon paper over treatment and they serve as strong polar sites to absorb water molecules, leading to improved hydrophilicity. Thus, the as-treated carbon papers with both increased specific surface areas and improved surface hydrophilicity exhibited excellent capacitive characteristics. Moreover, the charge/discharge test over 2000 cycles shows their excellent long-term capacitive retention. [ABSTRACT FROM AUTHOR]

The reduction of graphene oxide (GO) by means of thermal and/or chemical treatments leads to the production of reduced graphene oxide (rGO)—a material with improved electrical conductivity and considered a viable and low-cost alternative to pure graphene in several applications, including the production of supercapacitor electrodes. In the present work, GO was prepared by the oxidation of graphite recycled from spent Li-ion batteries using mixtures of sulfuric and phosphoric acids (with different H2SO4/H3PO4 ratios), leading to the production of materials with significant S and P contents. These materials were then thermally reduced, resulting in rGO papers that were investigated by solid-state 13C and 31P nuclear magnetic resonance, along with other methods. The electrochemical properties of the produced rGO papers were evaluated, including the recording of cyclic voltammetry and galvanostatic charge–discharge curves, besides electrochemical impedance spectroscopy analyses. The samples obtained by thermal reduction at 150 °C exhibited good rate capability at high current density and high capacitance retention after a large number of charge–discharge cycles. The results evidenced a strong relationship between the electrochemical properties of the produced materials and their chemical and structural features, especially for the samples containing both S and P elements. The methods described in this work represent, then, a facile and low-cost alternative for the production of rGO papers using graphite recycled from spent batteries, with promising applications as supercapacitor electrodes. [ABSTRACT FROM AUTHOR]

In the field of advanced energy storage, nanostructured Polyaniline (PANI) based materials hold a special place. Extensive studies have been done on the application of PANI in supercapacitors, however, the structure–property relationship of these materials is still not understood. This paper presents a detailed characterization of the novel sodium phytate doped 3D PANI nanofibers anchored on different types of carbon paper for application in supercapacitors. An excellent relationship between the structures and properties of the synthesized samples was found. Remarkable energy storage characteristics with low values of solution, charge transfer and polarization resistance and a specific capacitance of 1106.9 ± 1.5 F g−1 and 779 ± 2.6 F g−1 at current density 0.5 and 10 Ag−1, respectively, was achieved at optimized conditions. The symmetric supercapacitor assembly showed significant enhancement in both energy density and power density. It delivered an energy density of 95 Wh kg−1 at a power of 846 W kg−1. At a high-power density of 16.9 kW kg−1, the energy density can still be kept at 13 Wh kg−1. Cyclic stability was also checked for 1000 cycles at a current density of 10 Ag−1 having excellent retention, i.e., 96%. [ABSTRACT FROM AUTHOR]

Abstract The introduction of surface functional groups onto graphite can provide additional pseudocapacitance for supercapacitors. However, the compensation for the loss of electrical conductivity arising from the destruction of the π-π conjugation remains a big challenge. Here, the graphite paper is electrochemically oxidized first, followed by the mild reduction using hydroiodic acid to afford the largely exfoliated and moderately reduced sample (noted as MOGP-4). The as-prepared MOGP-4 not only has the abundant oxygenous groups, but also preserves the highly conductive network (sp2 carbon). Owing to the good conductivity (1.14 × 103 S m−1), MOGP-4 exhibits a high rate capability of 93% (from 18.3 mF cm−2 to 17 mF cm−2) as the current density increases from 0.5 to 10 mA cm−2 and predominant cycling performance. Furthermore, the flexible solid-state supercapacitors (SSCs) based on MOGP-4 with different sizes are assembled and deliver excellent durability, high flexibility and superior rate capability. The high electrochemical performances of the as-fabricated supercapacitors should envision promising applications for energy storage devices. Graphical abstract Image 1 highlights Graphite paper (GP) row material is low-cost, commercial, large-area and flexible. GP is electrochemically oxidized in mixed acids and then mildly reduced by HI. The strategy can introduce oxygenous groups and preserve high conductivity of GP. The fabricated SCs have high rate capability, stability and coulombic efficiency. [ABSTRACT FROM AUTHOR]

In recent era of modern and bendable technology, energy dearth arises as a paramount subject around the globe with a dire demand of flexible and lightweight energy storage devices. This study targets fabrication of reduced graphene oxide (rGO) and utility of abundantly available, cost effective, and environment friendly lignocelluloses (LC) fibers extracted from Carica papaya source, as a binder to bind active material (rGO) as robust and compact paper sheet. Fabricated samples were analyzed by X-ray diffraction for crystallographic analysis, Scanning electron microscopy, Transmission electron microscope for morphology, Fourier transform infrared spectroscopy for structural bonding, and Raman spectroscopy for vibrational modes. Robust and bendable rGO/LC paper electrode was tested for energy storage application by employing in different characterizations, i.e., cyclic voltammetry for capacitive behavior, galvanostatic charge–discharge for symmetric EDLC, and electrochemical impedance spectroscopy for resistive charge kinetics, respectively. rGO/LC composite sheet employed as working electrode in 3-electrode CV measurements and revealed specific capacitance of 591 F/g at a scan rate of 5 mV/s by keeping the undistorted shape of voltammograms at higher scan rates which present it as a suitable candidate for modern flexible and energy storage devices. rGO/LC-based symmetric cell revealed the highest specific capacitance of 228 F/g at applied current density of 0.1 A/g, the energy density of 6.3 Wh/kg, and power density of 129 W/kg, respectively. rGO/LC-based symmetric cell confirmed the cycling stability by revealing capacitance retention of 82% after 200 cycles. It can conclude that biomass-based rGO paper sheet can be a potential candidate as environmentally safe with remarkable electrochemical activity in energy storage applications. [ABSTRACT FROM AUTHOR]

Biosourced and biodegradable organic electrode materials respond to the need for sustainable storage of renewable energy. Here, we report on electrochemical capacitors based on electrodes made up of quinones, such as Sepia melanin and catechin/tannic acid (Ctn/TA), solution-deposited on carbon paper engineered to create high-performance interfaces. Sepia melanin and Ctn/TA on TCP electrodes exhibit a capacitance as high as 1355 mF cm−2 (452 F g−1) and 898 mF cm−2 (300 F g−1), respectively. Sepia melanin and Ctn/TA symmetric electrochemical capacitors operating in aqueous electrolytes exhibit up to 100% capacitance retention and 100% coulombic efficiency over 50,000 and 10,000 cycles at 150 mA cm−2 (10 A g−1), respectively. Maximum power densities as high as 1274 mW cm−2 (46 kW kg−1) and 727 mW cm−2 (26 kW kg−1) with maximum energy densities of 0.56 mWh cm−2 (20 Wh kg−1) and 0.65 mWh cm−2 (23 Wh kg−1) are obtained for Sepia melanin and Ctn/TA. Biosourced and biodegradable organic electrode materials are investigated for environmentally benign energy storage, but their performance at higher current density is often poor. Here, the authors construct electrodes with quinone-based species from Sepia melanin and tannins on treated carbon paper and observe electrode capacitance as high as 1355 mF cm−2 at current densities up to 10 A g−1. [ABSTRACT FROM AUTHOR]

Abstract Flexible micro-supercapacitors (FMSCs) are promising candidates for portable and on-chip energy storage due to their miniaturization, lightweight and high-security. Till now, FMSCs still suffer from several limitations, such as complex fabricating process, low areal energy storage, and short cycling lifetime, badly inhibiting its wider on-chip integrated applications. Here, we directly employ an easy-processing spray coating of the Ti 3 C 2 T x MXene conductive inks to massively fabricate the paper-based all-solid-state FMSCs. Instead of traditional noble metals Au as current collector, the sprayable and highly conductive Ti 3 C 2 T x MXene interdigitated electrodes serve the dual function of the active materials and current collection. Based on it, we develop an all-solid-state FMSC by employing polyvinyl alcohol & H 2 SO 4 gel-like solid-state electrolyte and self-flowed polydimethylsiloxane encapsulated layer. With further optimizing the geometric configurations of interdigitated electrodes, the as-prepared FMSCs exhibit high areal capacitance of 23.4 mF cm−2 and excellent rate-capability of 81.4%. Moreover, these paper-based FMSCs also demonstrate outstanding cyclic capability of 92.4% capacitance retention after 5000 cycles, along with remarkable flexibility. Consequently, we believe that this innovative strategy will open new avenues for easily and largely fabricating various FMSCs to further promote the integration of portable and on-chip energy storage systems. Graphical abstract Image 1 Highlights • It can easily achieve large-scale manufacturing and integration. • Ti 3 C 2 T x MXene acts as both the active material and current collection. • The configurations are optimized to obtain the best electrochemical performance. • Flexible paper-based micro-supercapacitors with excellent performance are obtained. [ABSTRACT FROM AUTHOR]

Abstract The electrode materials with large surface area and high porosity are predominant to enable the energy storage properties of electrochemical supercapacitors. Herein, lab-waste tissue paper templated trimanganese tetroxide hollow microtubes (Mn 3 O 4 HMTs) with high porosity on their walls were synthesized via a facile biomorphic method. Initially, aqueous manganese precursor was impregnated onto the surface of cellulose fibers by means of evaporation of water molecules. After thermal treatment under ambient atmosphere, the cellulose fibers were removed, which led to the formation of Mn 3 O 4 HMTs. The morphology, crystallinity and surface area of the prepared Mn 3 O 4 HMTs were examined by FE-SEM, XRD and BET analyses. When tested in aqueous alkaline electrolyte, the as-prepared Mn 3 O 4 HMTs delivered a maximum specific capacitance of 51.7 F g−1 at the current density of 1 mA cm−2 with good rate capability of 64.6% at high current density of 10 mA cm−2, which is due to the high porosity that enables an effective penetration of electrolyte ions. After 2000 cycles, the porous Mn 3 O 4 HMTs demonstrated good cycling stability of 57.1% at a current density of 5 mA cm−2. This facile method for the preparation of hollow structured materials could provide a deep insight into novel pseudocapacitive materials. Graphical abstract Image 1 Highlights • Mn 3 O 4 hollow microtubes (HMTs) were prepared using waste tissue papers as a template. • The Mn 3 O 4 HMTs exhibited large surface area and multilayered pores. • The as-synthesized material delivered a superior capacitance and good cycling stability. [ABSTRACT FROM AUTHOR]

With the increased awareness of environmental protection and the establishment of the spot market of electric power, renewable energy plays a more and more important role in energy structure adjustment. But the intermittence and instability of renewable energy often result in energy waste. Micro-grid energy storage can effectively improve the utilization rate, economy and reliability of renewable energy. To ensure the economical operation of the micro-grid system and improve the load curve, a two-stage optimal dispatch model was established based on non-dominated sorting genetic algorithm (NSGA-II) and deep Q-value reinforcement learning algorithm (DQN). In the first stage, to get the appropriate battery capacity, the minimum comprehensive operation cost and the minimum capacity fading of battery in the cycle life were selected as the optimization objectives. The optimal solution was calculated by using the improved non-dominated sorting genetic algorithm (NSGA-II). In the second stage, the DQN Algorithm was used to propose a scheduling strategy. Compared with the GA method, the DQN method was able to reduce the operating cost from 0.5829% to 1.2294%. The results showed that the method was feasible and effective. [ABSTRACT FROM AUTHOR]

Paper, as a traditional material for art and communication, shows great potential as a medium for organic user interfaces, with its ubiquity and flexibility. However, controlling and powering the sensors and actuators that enable interactive paper-crafts has not been fully explored. We present a method of selective inductive power transmission (SIPT) to support interactive paper-crafts. The novelty of this method is that the power transmitter can be controlled to selectively activate one specific receiver at a time through inductive power transferring with multiple receivers. This was achieved by changing the output frequency of the power transmitter to match the impedance of the receivers. The receivers could be embedded or printed to drive paper-crafts. Based on inductor–capacitor oscillating circuit and a function generator with a power amplifier, we developed two different prototypes of SIPT. By comparing the performance of both prototypes, we discussed the advantages and disadvantages of the two systems, and their applications in different contexts of paper-crafts. In addition, we proposed the instructions for using SIPT in developing interactive paper-crafts. With this technology and instructions, we hope to facilitate users to easily design new types of paper-craft systems without being concerned about the arrangement of wire connections to power supply on a massive scale. [ABSTRACT FROM AUTHOR]

Abstract: 3D carbon materials-supported MnO2 have promising application in energy storage as supercapacitor electrode materials. Here, we demonstrate a simple and scalable method to fabricate 3D carbon paper-supported MnO2 nanosheets, which can be used as supercapacitor electrode materials with low cost and high capacitance performance. MnO2 nanosheets with thickness about a few nanometers are grown on the carbon paper substrate through the reaction between aqueous KMnO4 and carbon. With the present method, the self-supported MnO2 composites can be fabricated into supercapacitor electrodes directly without any binder and conductive agents. It is found that MnO2 content in the composites increases with the increasing of KMnO4 concentration. The supercapacitor based on the hybrid with a MnO2 content of 7.9% exhibits the largest specific capacitance of 306.6 F g−1 at 0.5 A g−1, and a high power density of 67.8 kW kg−1 at the maximum current density of 300 A g−1. Moreover, the supercapacitors exhibit capacitance retention above 95% after 6000 cycles, demonstrating high stability of the carbon paper-supported MnO2 nanosheets for supercapacitors. Such 3D carbon paper-based architectures have promising application in energy storage devices with high power density and stability. [Copyright &y& Elsevier]

A flexible filter paper based composite electrode was prepared via the convenient one-step synthesis of silver doped graphene for the first time, followed by in-situ polymerization of aniline monomers. Using L-ascorbic acid for simultaneous reduction of grapheme oxide and silver nitrate, we provided a new and green method to prepare graphene hybrid sheets without toxicity. It was found that the as-fabricated hybrid electrode formed a three-dimensional porous architecture, which not only increased the specific surface area of composite, but also facilitated the ion diffusion of the electrolyte. In addition, according to the tests of electrochemical performances, the flexible hybrid electrode subsequently exhibited exceptional specific capacitance of 437.3 F/g, energy density of 1133.5 W·h/kg and power density of 88.8 kW/kg, respectively. Meanwhile, the as-prepared hybrid demonstrated a good cycling stability with only 10.99% specific capacitance deterioration after 5000 times of cycling. This preparation technology presented here shows great potential for the development and application of wearable and portable energy storage devices, particularly for flexible supercapacitors. Moreover, this study puts forward a general, simple and low-cost route of fabricating a novel flexible electrode on a large scale, eventually for environmental protection. [ABSTRACT FROM AUTHOR]

The increasing demands to further electrify and digitalize our society set demands for a green electrical energy storage technology that can be scaled between very small, and heavily distributed electrical energy sources, to very large volumes. Such technology must be compatible with fast-throughput, large-volume and low-cost fabrication processes, such as using printing and coating techniques. Here, we demonstrate a sequential production protocol to fabricate supercapacitors including electrodes based on cellulose nanofibrils (CNF) and the conducting polymer PEDOT:PSS. Thin and lightweight paper electrodes, carbon adhesion layers and the gel electrolyte are fabricated using spray coating, screen printing, and bar coating, respectively. These all solid-state supercapacitors are flexible, mechanically robust and exhibit a low equivalent series resistance (0.22 Ω), thus resulting in a high power density (∼104 W/kg) energy technology. The supercapacitors are combined and connected to a power management circuit to demonstrate a smart packaging application. This work shows that operational and embedded supercapacitors can be manufactured in a manner to allow for the integration with, for instance smart packaging solutions, thus enabling powered, active internet-of-things (IoT) devices in a highly distributed application. [ABSTRACT FROM AUTHOR]

[Display omitted] • A method for fabricating integrated multi-electrodes inside a single sheet of paper. • A paper used in two dimensions used as a three-dimensional scaffold. • The control of the equivalent circuit without changing external circuits and wires. Paper is an excellent substrate for flexible devices due to its various advantages such as flexibility, porosity, lightness, and thinness. Its inherent characteristics can be also exploited to overcome the limitations of conventional substrates, such as weak adhesion and large mass densities. Here, we propose a method for fabricating vertically integrated multi-electrodes within only a single sheet of paper. Despite the randomly distributed fibrous networks in a paper, the multi-layered electrodes were uniformly formed and completely separated by applying a removable hydrophobic wax barrier confinement inside a single sheet of paper. The integrated multi-layer electrodes inside a single sheet of paper mean that conventional two-dimensional planes can be used as three-dimensional scaffolds. The highly integrated electrodes and circuit systems are located within only a sheet of paper, making a new possibility to design maximizing the energy storage performance, integrated circuit systems, and significantly decreasing the thickness of the system without external complex structure. In consequence, this unique platform can circumvent most of the fabrication challenges related to two-dimensional energy storage sheets. [ABSTRACT FROM AUTHOR]

This paper addresses the assessment of woody biomass resources in Russia and the Baikal region. The analysis of the literature demonstrates that the Baikal region has considerable amounts of waste from the logging, timber processing, and pulp and paper industries (up to 220 PJ). A review of utilization technologies for woody biomass demonstrates that the existing technologies based on biomass gasification are promising for energy purposes. The gasification of biomass for small-capacity power plants has some advantages compared to its combustion. This paper considers an autonomous power system that consists of photovoltaic converters, wind turbines, storage batteries, a biomass gasification power plant, and a diesel power plant. A mathematical model used to optimize the system's structure finds the minimum of the total discounted costs for the creation and operation of the system with some constraints met. Based on mathematical modeling, the cost-effectiveness of such a power supply system is assessed for different climatic zones of the Baikal region and the coastal area of Lake Baikal. The findings indicate that the optimal solution is the integration of various renewable energy sources in hybrid power systems. The proportion of energy sources of different types in the installed capacities is found. The study demonstrates that the optimal structure of the power system can provide significant savings (the total discounted costs are reduced by almost 2.5 times compared to the option using a diesel power plant alone). [ABSTRACT FROM AUTHOR]

Fabrication of unconventional energy storage devices with high stretchability and performance is challenging, but critical to practical operations of fully power-independent stretchable electronics. While supercapacitors represent a promising candidate for unconventional energy-storage devices, existing stretchable supercapacitors are limited by their low stretchability, complicated fabrication process, and high cost. Here, we report a simple and low-cost method to fabricate extremely stretchable and high-performance electrodes for supercapacitors based on new crumpled-graphene papers. Electrolyte-mediated-graphene paper bonded on a compliant substrate can be crumpled into self-organized patterns by harnessing mechanical instabilities in the graphene paper. As the substrate is stretched, the crumpled patterns unfold, maintaining high reliability of the graphene paper under multiple cycles of large deformation. Supercapacitor electrodes based on the crumpled graphene papers exhibit a unique combination of high stretchability (e.g., linear strain ~300%, areal strain ~800%), high electrochemical performance (e.g., specific capacitance ~196 F g-1), and high reliability (e.g., over 1000 stretch/relax cycles). An all-solid-state supercapacitor capable of large deformation is further fabricated to demonstrate practical applications of the crumpled-graphene-paper electrodes. Our method and design open a wide range of opportunities for manufacturing future energy-storage devices with desired deformability together with high performance. [ABSTRACT FROM AUTHOR]

Wrinkled-paper-like ZnCo 2 O 4 nanoflakes were synthesized by a facile hydrothermal synthesis and a post-annealing treatment. As an anode for lithium-ion batteries, it exhibits high capacity, excellent cyclability and ultrahigh rate performance. A reversible capacity of 1138 mAh g −1 at 1 A g −1 was obtained after 500 cycles. After cycled at current densities from 0.2 to 25.6 A g −1 , the reversible capacity can recover to 1089 mAh g −1 at 0.2 A g −1 . It has been demonstrated that the wrinkled-paper-like ZnCo 2 O 4 nanoflakes are promising for application as future energy storage units. [ABSTRACT FROM AUTHOR]

Cobalt-based nanomaterials have received considerable attention in electric energy-storage devices due to their outstanding electrochemical characteristics. However, multiple time- and energy-consuming steps and complex reduction processes for producing cobalt and cobalt oxide nanostructures are disrupting their substantive commercialization. Here, we propose a facile, ultra-fast, and versatile method for the fabrication of cobalt and cobalt oxide nanostructures using an intense pulsed white light (IPWL) photothermal reduction technique. The mechanism of the IPWL photothermal reduction of cobalt and cobalt oxide is firstly studied by measuring the in-situ temperature of the Co(NO 3 ) 2 -coated carbon fiber paper (CFP) substrate during IPWL irradiation and analyzing the crystal structures of the IPWL-irradiated samples. Cobalt nanoflakes and cobalt oxide nanoparticles are synthesized on the surface of the CFP substrate by irradiating IPWL for 10 ms at ambient temperature and pressure with various energy densities from 10 to 30 J cm −2 . The Co 3 O 4 nanoparticle/CFP and Co nanoflake/CFP samples are further utilized as an electrode, and each electrode exhibits high specific capacity of 29 and 73 mA h g −1 , respectively, at a current density of 1 A g −1 . Since this novel photothermal reduction technique is applicable to other transition metals and metal oxides, it is a promising method for not only energy storage systems, but also for energy generation applications, filters, sensors, and catalysis systems. [ABSTRACT FROM AUTHOR]

• In-situ growth of MoS 2 over MnCO 3 inhibits formation of Mn-oxides/hydroxide. • MnCO 3 transforms to Mn(OH) 2 in aqueous KOH and stores charge by redox processes. • Mn(OH) 2 and MoS 2 afford low diffusion and charge transfer resistances, respectively. • MnCO 3 @MoS 2 hybrid utilized as negative electrode in asymmetric supercapacitor. This article puts forward a novel approach of combining the battery-type charge storage material, Mn(OH) 2 , indirectly with the two-dimensional material, MoS 2 , to develop the composite MnCO 3 @MoS 2 (designated as MCMS). A single-step facile hydrothermal method is described here for the synthesis of MCMS on a low-cost graphite substrate. Furthermore, this as-synthesized binder-free electrode is utilized as the negative electrode of an all-solid state asymmetric alkaline supercapacitor, employing NiCo 2 O 4 as the high specific energy positive electrode material. The overall asymmetric cell is shown to achieve a high specific energy of 48.97 W.h.kg −1 at 600 W.kg −1 and a high specific power of 12 kW.kg −1 at 11.33 W.h.kg −1, within a potential window of 1.2 V. Also, the composite electrode notably retains 86.5% of its gravimetric discharge capacity after 10,000 cycles with complete retention of its coulombic efficiency. The present work contributes to the development of a facile strategy for the preparation of non-carbonaceous hybrid materials suitable for high specific energy negative electrodes. [ABSTRACT FROM AUTHOR]

Potassium vanadium fluorophosphate (KVPO4F) is regarded as a promising cathode candidate for potassium-ion batteries due to its high working voltage and satisfactory theoretical capacity. However, the usage of electrochemically inactive binders and redundant current collectors typically results in inferior electrochemical performance and low energy density, thus implying the important role of rational electrode structure design. Herein, we have reported a scalable and cost-effective synthesis of a cellulose-derived KVPO4F self-supporting electrode, which features a special surface hydroxyl chemistry, three-dimensional porous and conductive framework, as well as super flexible and stable architecture. The cellulose not only serves as a flexible substrate, a pore-forming agent, and a versatile binder for KVPO4F/conductive carbon but also enhances the K-ion migration ability. Benefiting from the special hydroxyl chemistry-induced storage mechanism and electrode structural stability, the flexible freestanding KVPO4F cathode exhibits high-rate performance (53.0% capacity retention with current densities increased 50-fold, from 0.2 C to 10 C) and impressive cycling stability (capacity retention up to 74.9% can be achieved over 1,000 cycles at a rate of 5 C). Such electrode design and surface engineering strategies, along with a deeper understanding of potassium storage mechanisms, provide invaluable guidance for better electrode design to boost the performance of potassium-ion energy storage systems. [ABSTRACT FROM AUTHOR]

An asymmetric supercapacitor was prepared on a sheet of filter paper with two modified surfaces acting as electrodes in 1 M potassium hydroxide aqueous solution. By choosing carbon nanotubes and two different kinds of metal oxides (zinc oxide and ferro ferric oxide) as electrode materials, the asymmetric supercapacitor was successfully fabricated. The results showed that this device exhibited a wide potential window of 1.8 V and significantly improved electrochemical performances of its counterparts. Particularly, the one-sheet asymmetric supercapacitor demonstrated high energy density of 116.11 W h/kg and power density 27.48 kW/kg, which was attributed to the combined action and shortened distance between the two electrodes, respectively. Besides, it showed superior electrochemical cycling stability with 87.1% capacitance retention under room temperature. These outstanding results can not only give researchers new insights into compact energy storage systems, but they also provide a good prospect for flexible asymmetric supercapacitors. [ABSTRACT FROM AUTHOR]

With the rise of the 3Ds--decarbonization, decentralization, and digitalization--the number of electric vehicles is projected to increase, necessitating the implementation of modern technologies to avoid unnecessary energy wastage. Numerous studies have been developed proposing electric vehicle (EV) charging frameworks in networks empowered by renewable energy resources. In addition, more focus has recently been directed on incorporating blockchain technology to assure security and transparency in trading systems. However, fewer studies have delved into developing a practical implementation of their solution due to the complexity of the topic. Therefore, this paper thoroughly investigates integrating blockchain technology in electric vehicle charging systems, analyzing the existing practical implementation and their characteristics. It comprises 48 relevant studies between 2017 and 2023, covering the following main research areas: (i) renewable energy-based electric charging systems, (ii) blockchain frameworks used in energy trading, and (iii) performance metrics of simulated and implemented solutions. Results show that blockchain applications in EVs and energy trading systems are highly current, and researchers are actively exploring ways to improve their efficiency and effectiveness. [ABSTRACT FROM AUTHOR]

Abstract: Vanadium oxide has attracted interest for energy storage applications due to its high theoretical capacitance and stable layered structure. The low electronic conductivity, of V2O5 necessitates combining with conducting materials, typically carbon. However combining with conductive carbon materials may require binders, which compromise the active surface. In this study, V2O5 nanowire (VNWs)–graphene composite flexible paper electrodes were prepared without using binders. Graphene introduces conductivity and electric double layer capacitance (EDLC) to the composite. Graphene sheets were prepared using an alkaline deoxygenation process (hGO), which is a green alternative to traditional hydrazine reduction. Coin cell type supercapacitors were assembled using the hGO–VNW paper electrodes as the anode and spectracarb fiber cloth as the cathode in a two-electrode cell configuration. Electrochemical studies for different compositions of VNWs on hGO are reported. The composite electrode hGO–VNW120, showed balanced EDL and pseudocapacitance as well as an energy density of 38.8 Wh kg−1 at a power density of 455 W kg−1. The maximum power density of 3.0 kW kg−1 was delivered at a constant current discharge rate of 5.5 A g−1. The device prepared using hGO–VNW120 anode showed a specific capacitance of 80 F g−1. [Copyright &y& Elsevier]

The emergence of graphene paper comprising well-stacked graphene flakes has promoted the application of graphene-based materials in diverse fields such as energy storage devices, membrane desalination, and actuators. The fundamental properties of graphene paper such as mechanical, electrical, and thermal properties are critical to the design and fabrication of paper-based devices. In this study, the interlayer interactions in graphene paper were investigated by double cantilever beam (DCB) fracture tests. Graphene papers fabricated by flow-directed stacking of electrochemically exfoliated few-layer graphene flakes were mechanically separated into two parts, which generated force-displacement responses of the DCB sample. The analysis based on fracture mechanics revealed that the interlayer separation energy of the graphene paper was 9.83 ± 0.06 J/m2. The results provided a fundamental understanding of the interfacial properties of graphene papers, which will be useful for developing paper-based devices with mechanical integrity. [ABSTRACT FROM AUTHOR]

Supercapacitor is one kind of alternative energy storage devices. Constructing three-dimensional (3D) porous heterogeneous composite electrode materials is an important method to improve the performance of supercapacitor. Herein, we have used a simple solvothermal strategy to prepare NiCo2S4/Ni–Co LDH with a porous heterostructure grown on carbon fiber paper. The composite material is assembled from nanosheets into a 3D structure intertwined with each other. It possesses rich micro-pore size and exhibits excellent electrochemical properties. The unique structure favors for accelerating the electron transfer and electrolyte transport during the electrochemical process. At a current density of 10 mA cm−2, the specific capacitance is 1403 F g−1 (2.67 F cm2). When the current density is increased by 5 times, the specific capacitance is still as high as 1111 F g−1 (2.11 F cm2), showing good rate performance. Under a large current density of 30 mA cm−2, a long-term cycling performance of 5000 cycles has been evaluated. The capacitance retention reaches 111.1%, exhibiting outstanding cycle stability. Furthermore, the assembled symmetric supercapacitor device of also displays good electrochemical activities with an area capacitance of 0.19 F cm−2 at a current density of 3 mA cm−2, and superior cycling ability of high capacitance retention rate (115.4%) after 5000 cycles of charge and discharge process. The above results show that NiCo2S4/Ni–Co LDH is a promising candidate for high-performance supercapacitor. [ABSTRACT FROM AUTHOR]

Sandwiched paper for dielectric capacitors exhibited superior energy densities and high efficiencies under high voltages over a broad temperature range. [Display omitted] • Scalable fabrication of sandwiched GF in ANF paper for dielectric capacitors. • Excellent dielectric energy storage under high voltage over broad temperature range. • Sandwiched AGA5 paper exhibited ultrahigh breakdown strength at elevated temperatures. • Dielectric papers showed a record high U d of 11.7 J·cm−3 at 200 °C under 400 MV·m−1. High-performance capacitive energy storage under high voltages over a broad temperature range is eminently indispensable for the next generation of microelectronics and electrical power modules. The available dielectric polymer nanocomposites, unfortunately, are confined to the relatively low-temperature regimes (usually below 200 °C) and that hinders their practical applications. This work presents the scalable fabrication of highly thermostable phosphorous crosslinked aramid nanofiber (PANF) paper with a sandwiched layer of high aspect-ratio electrically insulating graphene fluoride (GF) nanosheets prepared by ultrasonic spraying. The sandwiched layer remarkably diminishes the conduction current density and dielectric loss, thereby imparting the ANF paper exceptional breakdown strength and much-enhanced energy density at elevated temperatures. Owing to the excellent combination of ultrahigh breakdown strength and large displacement (∼0.076 C·m−2 under 502 MV·m−1), the sandwich-structured AGA (PANF-GF-PANF) dielectric paper shows the maximal discharged energy density of 16.7 J·cm−3 with a charge–discharge efficiency of 86% at 30 °C and a record-high discharged energy density of 11.7 J·cm−3 with a charge–discharge efficiency of 87.2% under an applied electric field of 400 MV·m−1 at 200 °C. In addition, the flexible sandwich paper shows outstanding stability up to 500 °C. This work opens up new possibilities for the mass production of flexible high-temperature dielectrics for capacitive energy devices operating in harsh environments. [ABSTRACT FROM AUTHOR]

Laser-induced graphene (LIG) technology is qualified for manufacturing in-plane microsupercapacitors (MSCs) for its low cost and efficient fabrication. However, useable substrate and modification mechanism are mutual restricted for properties of materials. In this work, we creatively combine the chemical foaming strategy and laser-induced graphene technology based on commercial paper. Through a simple process, capacitance of assembled paper-based MSC is ∼350 times higher than control group without foaming and ∼7 times higher than device based on frequently-used polymer film. Specific areal capacitance and areal energy density reach up to 23.8 mF cm−2 and 2.64 μWh cm−2 respectively. This obvious capacitance enhancement is also accompanied by significantly reduced electrochemical impedance (almost two orders of magnitude smaller than unfoamed one) and excellent cycle performance (97% capacitance retention after 10000 cycles at high rates). It can be explained by distinct porous morphology, increased specific surface area (∼4 times higher than unfoamed material), changed N-doping type (increased pyridinic N) and improved product yield (∼2 times higher than control group) of the laser-induced foamed graphene (LIFG) material. The methodology proposed in this work paves a new avenue for modulating structures and components and improving electrode/electrolyte interface of carbon materials for high-performance energy storage devices. [Display omitted] • Combining chemical foaming and laser-induced technology to enhance capacitance. • As-prepared device is performing ∼350 times higher than unfoamed one. • Chemical foaming process changed the topography and composition of material. • Aramid papers are easier to be modified than frequently used PI films. [ABSTRACT FROM AUTHOR]

This review paper synthesizes the recent advancements in voltage regulation techniques for active distribution networks (ADNs), particularly in contexts with high renewable energy source (RES) penetration, using photovoltaics (PVs) as a highlighted example. It covers a comprehensive analysis of various innovative strategies and optimization algorithms aimed at mitigating voltage fluctuations, optimizing network performance, and integrating smart technologies like smart inverters and energy storage systems (ESSs). The review highlights key developments in decentralized control algorithms, multi-objective optimization techniques, and the integration of advanced technologies such as soft open points (SOPs) to enhance grid stability and efficiency. The paper categorizes these strategies into two main types: analytical methods and computational methods. In conclusion, this review underscores the critical need for advanced analytical and computational methods in the voltage regulation of ADNs with high renewable energy penetration levels, highlighting the potential for significant improvements in grid stability and efficiency. [ABSTRACT FROM AUTHOR]

With the widespread application of energy storage stations, BMS has become an important subsystem in modern power systems, leading to an increasing demand for improving the accuracy of SOC prediction in lithium-ion battery energy storage systems. Currently, common methods for predicting battery SOC include the Ampere-hour integration method, open circuit voltage method, and model-based prediction techniques. However, these methods often have limitations such as single-variable research, complex model construction, and inability to capture real-time changes in SOC. In this paper, a novel prediction method based on the KF-SA-Transformer model is proposed by combining model-based prediction techniques with data-driven methods. By using temperature, voltage, and current as inputs, the limitations of single-variable studies in the Ampere-hour integration method and open circuit voltage method are overcome. The Transformer model can overcome the complex modeling process in model-based prediction techniques by implementing a non-linear mapping between inputs and SOC. The presence of the Kalman filter can eliminate noise and improve data accuracy. Additionally, a sparse autoencoder mechanism is integrated to optimize the position encoding embedding of input vectors, further improving the prediction process. To verify the effectiveness of the algorithm in predicting battery SOC, an open-source lithium- ion battery dataset was used as a case study in this paper. The results show that the proposed KF-SA-Transformer model has superiority in improving the accuracy and reliability of battery SOC prediction, playing an important role in the stability of the grid and efficient energy allocation. [ABSTRACT FROM AUTHOR]

Integrated energy microgrids and shared energy storage have significant benefits in improving the energy utilization of the system, which is gradually becoming the current research hotspot. And the uncertainty of new energy output also significantly affects the stable and economic operation of integrated energy microgrid. So how to establish a set of integrated energy microgrids optimization operation model considering photovoltaic (PV) output uncertainty and shared energy storage is an urgent problem to be solved nowadays. Firstly, this paper introduces the framework of an integrated energy system microgrid containing a shared energy storage operator (ESO), and analyzes the scheduling method of the upper tier operator within the system as well as the economic benefits at the lower tier user end. Secondly, to address the randomness of PV output, Monte Carlo method is used to generate the scenarios, and then the scenarios are cut down by using the fast antecedent elimination technique. Then, an optimal operation model is established for micro grid operator (MGO) and user aggregator (UA), respectively, and based on the master-slave game relationship, so that the MGO is the leader and the UA is the follower, a Stackelberg game model is proposed to consider the integrated demand response of electricity and heat between the MGO and UA in the context of the participation of ESO in the auxiliary service of the UA. Finally, the proposed model is brought into a typical residential building community for simulation verification, and the results show that the model proposed in this paper can effectively balance the interests of MGOs and UAs, and realize win-win benefits for UA and ESO. [ABSTRACT FROM AUTHOR]