Search

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]

The growing demands of sustainable, portable, and wearable electronics pose new demands on miniaturized energy storage devices that can be integrated on flexible substrates such as paper. Microsupercapacitors (MSCs), especially MXene‐based pseudocapacitive MSCs with fast charging/discharging rate, high power density, and long cycle life, are competitive candidates as power supply for emerging flexible and wearable on‐paper electronics. However, few studies have reported MXene‐based on‐paper MSCs to simultaneously attain ultrahigh‐rate (>1000 mV s−1) capability and large areal capacitance >10 mF cm−2. Herein, ultrafast metal‐free on‐paper MSCs are fabricated through leveraging the synergistic effect of conductive PEDOT:PSS and capacitive MXene (Ti2C) to achieve a remarkable areal capacitance of 30 mF cm−2 and long lifetime (>96% capacitance retention after 10 000 cycles) at an ultrahigh scan rate of 1000 mV s−1, outperforming most of the present on‐paper or MXene‐containing MSCs. Moreover, the printed on‐paper metal‐free MSC arrays attain extended working voltage window of up to 6 V and outstanding capacitive performance at an ultrahigh scan rate of 10 V s−1. The on‐paper PEDOT:PSS‐Ti2C composite MSCs offer new opportunities as eco‐friendly microscale power sources for emerging paper‐based portable and wearable electronics. [ABSTRACT FROM AUTHOR]

The design of high‐performance electrode material without compromising energy and power density is critical for the advancement in hybrid electric vehicle technology. In this perspective, we have fabricated a MnO2 loaded activated charcoal‐based electrode on graphite paper as an endeavour to improve the energy storage capabilities. The electrode material is synthesized by employing a sustainable route and the structural, microstructural, and textural properties have been investigated. The electrochemical performance for energy storage is evaluated and the fabricated electrode on graphite paper exhibits remarkably high‐power density (811 W kg−1) maintaining high energy density (106 Wh kg−1) at the same time, along with high gravimetric specific capacitance value of 768 F g−1 at 2 mA cm−2. The obtained results demonstrate the excellent performance of the electrode material, suggesting MnO2 loaded activated charcoal as a prospective electrode material to meet the demand of hybrid electric vehicles as well as to contribute to our transitioning towards low‐to‐zero carbon emission technology. [ABSTRACT FROM AUTHOR]

In this study, a redox reaction is employed to synthesize manganese oxide (Mn3O4) nanoparticles using potassium permanganate as a precursor in the presence of diethyl amine. The structural characterization reveals the formation of the tetragonal phase of Mn3O4 nanoparticles with a space group of I41/amd. A free‐standing Mn3O4‐based paper electrode is fabricated and its electrochemical performances are investigated. The electrode exhibits a maximum specific capacitance value of ~353 F g−1 and an areal capacitance of ~530 mF cm−2 at a current density of 0.2 A g−1. A symmetric supercapacitor‐based device is also designed using Mn3O4 nanoparticles as an active material in a gel electrolyte configuration. The Mn3O4 device achieves specific and areal capacity values of ~208 mAh g−1 and 260 mA cm−2, respectively, at a current density of 0.3 A g−1. The device delivers maximum energy and power density values of ~104 Wh kg−1 and ~220 W kg−1, respectively, with ~92 % specific capacity retention at 0.3 A g−1 after 5000 cycles. The above results suggest that the Mn3O4‐based device has the potential for energy storage applications. [ABSTRACT FROM AUTHOR]

Laser-induced graphene (LIG) is as a promising material for flexible microsupercapacitors (MSCs) due to its simple and cost-effective processing. However, LIG-MSC research and production has been centered on non-sustainable polymeric substrates, such as polyimide. In this work, it is presented a cost-effective, reproducible, and robust approach for the preparation of LIG structures via a one-step laser direct writing on chromatography paper. The developed strategy relies on soaking the paper in a 0.1 M sodium tetraborate solution (borax) prior to the laser processing. Borax acts as a fire-retardant agent, thus allowing the laser processing of sensitive substrates that other way would be easily destroyed under the high-energy beam. LIG on paper exhibiting low sheet resistance (30 Ω sq−1) and improved electrode/electrolyte interface was obtained by the proposed method. When used as microsupercapacitor electrodes, this laser-induced graphene resulted in specific capacitances of 4.6 mF cm−2 (0.015 mA cm−2). Furthermore, the devices exhibit excellent cycling stability (> 10,000 cycles at 0.5 mA cm−2) and good mechanical properties. By connecting the devices in series and parallel, it was also possible to control the voltage and energy delivered by the system. Thus, paper-based LIG-MSC can be used as energy storage devices for flexible, low-cost, and portable electronics. Additionally, due to their flexible design and architecture, they can be easily adapted to other circuits and applications with different power requirements. [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.

Ultrathin devices are rapidly developing for skin‐compatible medical applications and wearable electronics. Powering skin‐interfaced electronics requires thin and lightweight energy storage devices, where solution‐processing enables scalable fabrication. To attain such devices, a sequential deposition is employed to achieve all spray‐coated symmetric microsupercapacitors (μSCs) on ultrathin parylene C substrates, where both electrode and gel electrolyte are based on the cheap and abundant biopolymer, cellulose. The optimized spraying procedure allows an overall device thickness of ≈11 µm to be obtained with a 40% active material volume fraction and a resulting volumetric capacitance of 7 F cm−3. Long‐term operation capability (90% of capacitance retention after 104 cycles) and mechanical robustness are achieved (1000 cycles, capacitance retention of 98%) under extreme bending (rolling) conditions. Finite element analysis is utilized to simulate stresses and strains in real‐sized μSCs under different bending conditions. Moreover, an organic electrochromic display is printed and powered with two serially connected μ‐SCs as an example of a wearable, skin‐integrated, fully organic electronic application. [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]

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]

A paper‐based supercapacitor (SC) is a promising flexible energy storage device for wearable electronics. Paper is an alternative flexible substrate to conventional substrates such as metal foil or plastics. Paper's porous structure can be applied as a large surface area of electrode to store more charge. Paper can also be used as a separator between each electrode. We propose a simple method for vertically integrating a multi‐pair of interdigital electrodes within only a single sheet of paper. The integrated multi‐electrodes were fully separated because of a removable wax barrier. The integrated multi‐pair interdigital electrodes in a paper were used as ultra‐thin SCs combined in parallel. With an inner space of paper, the device volume can be reduced with high energy density while preserving flexibility. The energy density was 86.58 μWh cm−2, which is three orders of magnitude higher energy density than a single SC at the same size. [ABSTRACT FROM AUTHOR]

MXene is a promising energy storage material for miniaturized microbatteries and microsupercapacitors (MSCs). Despite its superior electrochemical performance, only a few studies have reported MXene‐based ultrahigh‐rate (>1000 mV s−1) on‐paper MSCs, mainly due to the reduced electrical conductance of MXene films deposited on paper. Herein, ultrahigh‐rate metal‐free on‐paper MSCs based on heterogeneous MXene/poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonate) (PEDOT:PSS)‐stack electrodes are fabricated through the combination of direct ink writing and femtosecond laser scribing. With a footprint area of only 20 mm2, the on‐paper MSCs exhibit excellent high‐rate capacitive behavior with an areal capacitance of 5.7 mF cm−2 and long cycle life (>95% capacitance retention after 10,000 cycles) at a high scan rate of 1000 mV s−1, outperforming most of the present on‐paper MSCs. Furthermore, the heterogeneous MXene/PEDOT:PSS electrodes can interconnect individual MSCs into metal‐free on‐paper MSC arrays, which can also be simultaneously charged/discharged at 1000 mV s−1, showing scalable capacitive performance. The heterogeneous MXene/PEDOT:PSS stacks are a promising electrode structure for on‐paper MSCs to serve as ultrafast miniaturized energy storage components for emerging paper electronics. [ABSTRACT FROM AUTHOR]

A high-performance paper electrode is fabricated through coating polypyrrole (PPy) on ordinary laboratory filter paper via a traditional interfacial polymerization method with perchloric acid (HClO4) as a dopant. Owing to the superior mechanical flexibility and environmental stability of the free standing PPy paper, the robust electrode displays an ultrahigh capacitance of 1650 mF cm−2 and remarkable cyclic stability of losing 11.66% after cycling for 10000 times in a three-electrode system. More importantly, the areal specific capacitance has only decreased by 0.08% after five months. Furthermore, by employing the synthesized PPy papers as electrodes and the PVA-H2SO4 gel as electrolyte, the assembled all-solid-state supercapacitor with an areal specific capacitance of 566.5 mF cm−2 is achieved, corresponding to an areal energy density of 38.55 μW h cm−2 and power density of 0.17 mW cm−2. These results suggest that the simple synthesis of PPy paper electrode pave a promising way to exploit flexible and durable energy storage applications. [ABSTRACT FROM AUTHOR]

The terrible shuttling of lithium polysulfides (LiPSs) is a major obstacle for commercializing lithium–sulfur (Li–S) batteries as high‐performance energy storage systems. In this study, a carbon‐based interlayer with effective suppression capability on the shuttle effect is developed by simply coating a well‐dispersed mixture of soybean protein isolate/MXene onto the acidified carbon paper (ACP). The resultant composite interlayer (SM@ACP) is able to synergistically diminish the shuttle effect through chemical adsorption and physical blocking. Meanwhile, this interlayer displays excellent conductivity and facilitates the diffusion of Li ions due to the composite coating to promote both electron/ion conduction as well as the porous structure of ACP. Benefiting from the unique properties of the composite interlayer, the as‐assembled Li–S batteries with SM@ACP interlayers show a great improvement in the cycling stability and rate performance, delivering a very low‐capacity decay rate of 0.071% per cycle at 0.5 C even after 800 cycles. This work provides a feasible route to realize rational design and commercial mass production of desirable interlayers for promoting the commercialization of Li–S batteries. [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]

In recent years, there has been an increased focus on studying light–battery interactions in the context of operando optical studies and integrated photoelectrochemical energy harvesting. However, there has been little insight into identifying suitable "light‐accepting" current collectors for this class of batteries. In this study, fluorine‐doped tin oxide, indium‐tin oxide, and silver nanowire‐graphene films are analyzed along with carbon paper, carbon nanotube paper, and stainless‐steel mesh as current collectors for optical batteries. They are categorized into two classes – transmissive and non‐transmissive, based on the orientation of the light–electrode interaction. Various methods to prepare the electrode are highlighted, including drop casting and the fabrication of free‐standing electrodes. The optical and electrical properties of these current collectors as well as their electrochemical stability are measured using linear sweep voltammetry against zinc and lithium anodes. Finally, the rate performance and long‐term cycling stability of lithium manganese oxide (LiMn2O4) cathodes are measured against lithium anodes with these current collectors and their performance is compared. These results show which current collector to choose depends on the application and cell chemistry. These guidelines will assist in the design of future optical cells for in‐situ measurements and photoelectrochemical energy storage. [ABSTRACT FROM AUTHOR]

Using synergetic effects of various sodium storage modes and materials to construct high power, high energy, and long cycling flexible sodium anode materials is significant and still challenging. Here, by advantageous functional integration of adsorption‐intercalation‐conversion sodium storage mechanisms, a 3D flexible fiber paper anode with the composition of Nb2O5@hard carbon@MoS2@soft carbon is designed and prepared. Based on the synergetic effects, it exhibits higher specific capacity than pure Nb2O5, with more excellent rate performance (245, 201, 155, 133, and 97 mAh g−1 at the current density of 0.2, 1, 5, 10, and 20 A g−1, respectively) than pure MoS2 as well as admirable long‐term cycling characteristics (≈82% capacity retention after 20 000 cycles at 5 A g−1). Relevant kinetics mechanisms are expounded in detail. This work can be helpful for preparing other types of hybrid and flexible electrodes for energy storage systems. [ABSTRACT FROM AUTHOR]

[Display omitted] The design and synthesis of advanced electrodes with high conductivity and flexibility are the key to the development of wearable energy storage devices. Herein, a strategy for preparing conductive carbon paper electrode for flexible supercapacitors is reported by vacuum filtration of a mixture of biomass hierarchical porous carbon materials (HPC), cellulose nanofibers (CNFs) from polysaccharide cellulose of plant origin and silver nanowire (AgNWs), in which CNFs serve as substrates for dispersion and crosslinking of HPC. The prepared self-supporting electrode showed multi-scale pore structure and excellent conductivity (14.1 S cm−1). The electrode exhibited the highest specific capacitance of 383 F g−1 at 0.5 A g−1. Even after 10,000 charge and discharge cycles, 95 % of the original capacitance was remained, which means excellent cyclic stability. High strength and flexibility of the as-assembled flexible supercapacitor make the electrochemical performance of this device remain unchanged when bent at any angle. The present research delineates a simple and convenient method to prepare green, efficient and low-cost flexible supercapacitor. [ABSTRACT FROM AUTHOR]

The lithium-sulfur battery (LSB) is a highly promising energy storage system with merits of exceptional theoretical specific capacity and energy density. However, challenges including insufficient sulfur conductivity, volume expansion, and the polysulfide shuttle effect result in rapid capacity decay and limited cycle life of the LSB, which significantly hinders its development. Inspired by the structure and forming process of paper, a fiber double network skeleton was constructed using flexible pulp fiber (PF) and highly conductive carbon fiber (CF). Following the principles of wet end chemistry in papermaking, MXene nanosheets with high adsorption and catalytic capacity for polysulfides were self-assembled on the surfaces of PF and CF to fabricate composite paper-based materials. The interwoven mesh of PF exhibited strong binding force and stable structure, providing support and protection for the CF interwoven mesh, resulting in a composite material with abundant porosity and excellent structural stability. Moreover, the CF interweaving network combined with an overlaid MXene interweaving network established an effective three-dimensional conductive pathway. When utilized as a self-supporting cathode in LSB, this composite paper-based material demonstrated outstanding cyclic stability. Under conditions of sulfur load at 2.3 mg·cm−2 and discharge at 0.2 C, the specific discharge capacity remained at 952 mAh·g−1 after 200 cycles with a capacity retention rate reaching 95.4%. The CF/PF@Mxene (CPCMX) also exhibited excellent tensile strength measured at 7.19 MPa while maintaining exceptional flexibility and electrolyte wettability. This research presents a highly promising solution for advancing the development of LSB with superior cycle stability. [ABSTRACT FROM AUTHOR]

In this paper, carbon paper as positive electrode for vanadium redox flow battery was etched by chlorosulfonic acid with assistance of ultrasonication. Carbon layer-exfoliated, wettability-enhanced, SO 3 H-functionalized carbon paper was successfully achieved by facile treatment. The electrochemical kinetics of VO 2+ /VO 2 + redox reaction on carbon paper was significantly improved after the treatment. Carbon paper after ultrasonication-assisted treatment exhibits better electrochemical activity compared with the untreated and only-soaking samples. The cell using treated carbon paper as positive electrode shows larger discharge capacity and higher energy efficiency compared with the pristine cell. The initial discharge capacity of the cell using optimal treated carbon paper reaches 127.7 mA h, 20.8 mA h larger than that of the pristine one at 50 mA cm −2 . Furthermore, the average energy efficiency increases by 5.1% by using the treated electrode. The introduced sulfonic groups as active sites and increased surface area by etching can reduce the electrochemical polarization of VO 2+ /VO 2 + redox reaction. Moreover, the improved wettability of treated carbon paper can accelerate mass transfer of active species. Therefore, the reduced electrochemical polarization and accelerated mass transfer of active species conjointly cause the enhanced electrochemical properties of the treated carbon paper. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The development of flexible current collectors as an indispensable component in energy storage devices has been in strong demand for the ever-growing market of flexible and wearable electronics. Herein, flexible and conductive paper-based current collectors are fabricated by directly depositing a metallic Ni layer composed of spiny Ni nanospheres of 400 nm diameter on the surface of filter paper via electroless deposition. The metallic paper shows excellent electric and mechanical properties: the sheet resistance is 2.7 Ω cm−2 (R0 = 0.8 Ω cm−2) after 5000 bending cycles and the mass density is only 0.35 g cm−3. MnO2 is selected as an electrode active material to explore the role of flexible and conductive paper-based current collectors in supercapacitors. Electrochemical results reveal that the largest areal specific capacitance is 1095 mF cm−2 at 1 mA cm−2 and the excellent electrochemical performance can be attributed to the hierarchical porous fibre structure of paper and the lower contact resistance between the active material and the current collector. Note that the approach can be applied to an enlarged size of metallic conductive paper or textile, presenting a simple and feasible method to fabricate flexible current collectors in a large scale. [ABSTRACT FROM AUTHOR]

In response to the request for sustainable high performance energy storage devices, a significant interest is focused on developing environmentally friendly supercapacitors. In this context, cellulose‐based substrates for energy storage devices can be well‐engineered, lightweight, safe, thin, and flexible. Herein, a scalable, low‐cost, and easy‐to‐process approach for the preparation of supercapacitors using large area techniques like spray and blade coating is presented. Following a green strategy, all components are chosen or formulated in water‐based dispersions. Symmetric supercapacitors using common copy paper and electronic paper as the substrate, and poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonate) (PEDOT:PSS) as electrodes, are realized and investigated. The novelty of this work consists of the use of composites based on detonation nanodiamonds (DNDs) and hydroxypropyl cellulose (HPC) as a solid‐state electrolyte and separator. Devices with solution electrolyte using the same HPC + DND composite but with the addition of sodium sulfate are prepared. The performance obtained using solid electrolyte (HPC + DNDs) and liquid electrolyte (HPC + DNDs + Na2SO4) on both substrates is comparable in terms of specific capacitance: ≈0.13 – 0.52 F g−1 for (HPC + DNDs) and ≈0.35 – 0.82 F g−1 for (HPC + DNDs + Na2SO4), with power density in the range of ≈19 – 24 μW cm−2. [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]

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.

Mulberry paper comprising holocellulose shows excellent mechanical and chemical stability suitable for paper-based electronics. However, most studies pertaining to paper-based electronics have used conventional paper. Therefore, in this study, we demonstrated Ag nanoparticle (AgNP)/Ag nanowire (AgNW) flexible composites on mulberry-paper substrates. The AgNP/AgNW composites were fabricated by the dry transfer method, where the AgNP/AgNW layers were transferred from a polymer substrate with a hydrophobic surface to the toner-printed mulberry paper via hot pressing. Microstructural analysis showed that the mulberry papers contained thicker fibres than those in conventional papers, which limited the uniform transfer of the AgNP/AgNW layers on the mulberry papers. Therefore, we optimised the hot pressing conditions to 30 MPa and 80 °C, which allowed for the successful formation of the AgNP/AgNW composites on mulberry papers. Cyclic bending test results over 10,000 cycles revealed that the mulberry-paper-based composites showed better mechanical reliability with 30–40% smaller increases in resistance compared to those in conventional A4-paper-based composites. Lastly, a flexible supercapacitor fabricated using the mulberry-paper-based composite as the current collector showed excellent reliability without significant capacitance degradation over 100 bending cycles. [ABSTRACT FROM AUTHOR]

Developing new energy technology is a significant challenge in the context of the energy crisis. As a novel energy conversion device to convert mechanical energy into electricity, the triboelectric nanogenerator (TENG) has attracted significant attention in the past few years. The choice of component materials directly affects the cost, environmental performance, output performance, and preparation process of a TENG. In recent years, cellulose paper has become an ideal material for fabricating a TENG due to its lightweight, biodegradability, low‐cost, high flexibility, environmental friendliness, porosity, and easy modification. Cellulose paper‐based TENG has become a hot topic in the field of green energy. This paper systematically summarizes the research progress of the cellulose paper‐based TENG. The advantages of cellulose paper as raw material to fabricate a TENG, followed by introducing the different roles of cellulose paper in paper‐based TENGs, are first discussed. Then the recent progress in energy storage, performance optimization methods, hybridization, and applications of cellulose paper‐based TENGs is successively elaborated. Finally, some perspectives and challenges for the future development of cellulose paper‐based TENG are discussed to provide guidance. [ABSTRACT FROM AUTHOR]

In the quest for greener and more efficient energy storage solutions, the exploration and utilization of renewable raw materials is essential. In this context, cellulose-derived separators play a central role in enhancing the performance of green energy storage devices. However, these often exhibit disadvantageous porosity and limited wet strength. Here, we demonstrate a facile approach to tailor thickness (ca. 40 μm), air permeability (0.1–200 cm3 s−1), and mechanical properties of separators by integration of up to 50 wt% microfibrillated cellulose (MFC) into paper sheets. While the MFC enhanced the formation of dense networks, these separators show a poor dimensional stability (folding and creasing) concomitant with a low strength under wet conditions, crucial for assembly and operation. Crosslinking with 1,2,3,4-butanetetracarboxylic acid (BTCA) however, led to an increase in wet strength by up to 6700 % while ensuring dimensional stability. The electrochemical performance, evaluated by impedance spectroscopy and galvanostatic cycling (7500 repetitions) showed comparable results as commercially available glass and polypropylene separators in terms of ion diffusion, charge-discharge rate performance, Ohmic loss and capacitance retention %. The approach demonstrates that disadvantages of paper-based separators in terms of dimensional stability and wet strength can be overcome by a paper technological approach using crosslinking strategies. [Display omitted] [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]