Waste Tire Derived Carbon-Polymer Composite Paper as Pseudocapacitive Electrode with Long Cycle Life

Insights into molecular interactions at organic-MBene heterointerfaces for efficient Zn-ion storage

The intercalation of organic molecules is a promising approach to modulate the structure of 2D transition metal borides (MBenes), aiming to enhance charge transport and improve electrochemical performance in energy storage applications. However, key questions remain regarding how organic molecules with diverse functionalities penetrate and align between the MBene layer, as well as the mechanism of charge redistribution during intercalation. Addressing these questions is crucial for guiding the design of Organic-MBene heterostructures. To this end, a comprehensive approach combining theoretical calculations and experimental analyses was employed to explore the self-assembly mechanisms of organic molecules featuring N, O, S and tertiary amine end groups on the MoB-MBene surface. Experimental characterizations confirm that the interaction between MoB and organic compounds depends on the end groups. First principles calculations demonstrate that organic molecules tend to adopt a flat configuration on the MoB surface during molecular assembly. Calculations also reveal that the binding and charge transfer processes from organic molecules to MoB are highly dependent on the specific end groups, consistent with experimental observations. Furthermore, the effect of combining organic molecules with MoB on battery performance was further discussed, offering new insights for advancing the research and development of MBenes in aqueous battery systems.

Tailoring a hierarchical porous carbon electrode from carbon black via 3D diatomite morphology control for enhanced electrochemical performance

Carbon black, a nano-porous material usually derived from the pyrolysis of waste tyres possesses varied particle sizes and morphology making it a viable material for several engineering applications. However, the high tendency for CB to agglomerate remains a challenge. To address this, bio-templating has been employed to produce a nanostructured porous carbon electrode material for supercapacitor applications using diatomite as a template. Diatomite-synthesized activated carbon (DSAC) was fabricated through a three-step process involving acid treatment of diatomite, thermal activation of carbon black, and bio-template synthesis. The resulting material was thoroughly characterized using XRD, Raman spectroscopy, BET analysis, and SEM imaging. Its electrochemical properties were assessed through cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. The DSAC material exhibited a high specific surface area of 266.867 m2 g-1, pore volume of 0.6606 cm3 g-1, and mean pore radius of 1.8943 nm. The electrochemical evaluation revealed that DSAC demonstrates excellent electrochemical performance, achieving a high specific capacitance of 630.18 F g-1 and retaining 94.29% capacitance after 5000 cycles at 1 A g-1. The DSAC electrode is eco-friendly and a promising candidate for supercapacitor applications.

End-of-life tyre conversion to energy: A review on pyrolysis and activated carbon production processes and their challenges

The number of end-of-life waste tyres has increased enormously worldwide, which is one of the non-biodegradable Municipal Solid Waste (MSW) piling up in an open space for a long time. Every year, various types of tyres are released in the environment from different vehicles, such as trucks, buses, cars, motorcycles, and bicycles, which negatively impact the environment. Nowadays, waste tyres are treated in several ways, whereas thermochemical conversion is one of them, including combustion, gasification, incineration, and pyrolysis. Many literatures revealed that pyrolysis is a more environmentally friendly process than others since it can convert waste tyres into crude oil, char, and syngas without emitting harmful gases. In this study, the pyrolysis of tyres and the chemical activation of tyres are reviewed in terms of their kinetic behaviour. According to the literature, the most influential factors of the pyrolysis process are reactors, temperature, heating rate, residence time, feedstock size and catalyst. As the main ingredient of the tyre is rubber, tyre pyrolysis starts from 300 °C and completely decomposed nearly 550 °C. It can be found from literature that Pyrolysed tyre can produce 30-65% oil, 25-45% char and 5-20 % gas. It is also explained how the properties of active carbon (AC) are affected by activating conditions, including activation temperature, agent, the ratio of reagent mixture and others. Generally, pyrolytic char has surface area between 20 and 80 m2/g, whereas tyre-derived activated carbon's (TDAC) surface area varied from 90 to 970 m2/g. For large surface area and porous structure, TDAC has large application in purification and energy storage sector. The individuality of this article is to depict the entire pathway of AC production from waste tyres. The findings of this literature review help to improve technologies for producing activated carbon from waste tyres pyrolysed char.

Ag(e)ing and Degradation of Supercapacitors: Causes, Mechanisms, Models and Countermeasures

The most prominent and highly visible advantage attributed to supercapacitors of any type and application, beyond their most notable feature of high current capability, is their high stability in terms of lifetime, number of possible charge/discharge cycles or other stability-related properties. Unfortunately, actual devices show more or less pronounced deterioration of performance parameters during time and use. Causes for this in the material and component levels, as well as on the device level, have only been addressed and discussed infrequently in published reports. The present review attempts a complete coverage on these levels; it adds in modelling approaches and provides suggestions for slowing down ag(e)ing and degradation.

Advances of Biowaste-Derived Porous Carbon and Carbon–Manganese Dioxide Composite in Supercapacitors: A Review

One of the global problems is environmental pollution by different biowaste. To solve the problem, biowaste must be recycled. Waste-free technology is also a way of saving exhaustible raw materials. Research on electrochemical energy sources is currently the most dynamically developing area of off-grid energy. Electrochemical capacitors can operate for a long time without changing performance, they have smaller dimensions, high mechanical strength, and a wide operating temperature range. These properties are effective energy-saving devices. Therefore, supercapacitors are widely used in various industries. This review discussed the methods of obtaining and the characteristics of biowaste-derived activated carbon and carbon–manganese oxide (AC-MnO2)-based supercapacitor electrodes.

Waste tire derived carbon as potential anode for lithium-ion batteries

The uncontrolled accumulation of end-of-life tires every year leads to serious environmental concerns, rendering setback to the sustainable growth of the society. The most viable solution to overcome this environmental issue is to convert these hazardness waste tires into value added products. In the present investigation, carbonecous based anode materials has been developed by a novel chemical activation strategy involving aqua regia followed by controlled pyrolytic condition in the selective atmospheres. Raman spectroscopic study displayed a graphitic carbon with significant degree of disordered arrangements. The generation of the turbostratic carbon with higher content of broken crystal edges is corroborated using the structural characterization such as X-ray diffraction (XRD). This fact is further corroborated from surface energy results calculated using the contact angles measured by dynamic wicking method. The prepared turbostratic carbon, when used as lithium anode, renders excellent electrochemical performances with reversible specific capacity of 350 mAhg^-1 (at 300 mAg^-1) with 81% capacity retention after 500 cycles. The present research provides new roadmap in recycling the waste tires for energy storage applications.

Upcycling Plastic Waste into High Value-Added Carbonaceous Materials

Even though plastic improved the human standard of living, handling the plastic waste represents an enormous challenge. It takes more than 100 years to decompose discarded or buried waste plastics. Microplastics are one of the causes of significantly pervasive environmental pollutants. The incineration of plastic waste generates toxic gases, underscoring the need for new approaches, in contrast to conventional strategies that are required for recycling plastic waste. Therefore, several studies have attempted to upcycle plastic waste into high value-added products. Converting plastic waste into carbonaceous materials is an excellent upcycling technique due to their diverse practical applications. This review summarizes various studies dealing with the upcycling of plastic waste into carbonaceous products. Further, this review discusses the applications of carbonaceous products synthesized from plastic waste including carbon fibers, absorbents for water purification, and electrodes for energy storage. Based on the findings, future directions for effective upcycling of plastic waste into carbonaceous materials are suggested.

Recent Advances in Waste Plastic Transformation into Valuable Platinum-Group Metal-Free Electrocatalysts for Oxygen Reduction Reaction

Plastic waste causes severe environmental hazards, owing to inadequate disposal and limited recycling. Under the framework of circular economy, there are urgent demands to valorize plastic waste more safely and sustainably. Therefore, much scientific interest has been witnessed recently in plastic waste-derived electrocatalysts for the oxygen reduction reaction (ORR), where the plastic waste acts as a cost-effective and easily available precursor for the carbon backbone. The ORR is not only a key efficiency indicator for fuel cells and metal-air batteries but also a major obstacle for their commercial realization. The applicability of the aforementioned electrochemical devices is limited, owing to sluggish ORR activity and expensive platinum-group metal electrocatalysts. However, waste-derived ORR electrocatalysts are emerging as a potential substitute that could be inexpensively fabricated upon the conversion of plastic waste into active materials containing earth-abundant transition metals. In this Minireview, very recent research developments regarding plastic waste-derived ORR electrocatalysts are critically summarized with a prime focus on the followed synthesis routes, physicochemical properties of the derived electrocatalysts, and their ultimate electrochemical performance. Finally, the prospects for the future development of plastic waste-derived electrocatalysts are discussed.

The Positive Effect of ZnS in Waste Tire Carbon as Anode for Lithium-Ion Batteries

There is great demand for high-performance, low-cost electrode materials for anodes of lithium-ion batteries (LIBs). Herein, we report the recovery of carbon materials by treating waste tire rubber via a facile one-step carbonization process. Electrochemical studies revealed that the waste tire carbon anode had a higher reversible capacity than that of commercial graphite and shows the positive effect of ZnS in the waste tire carbon. When used as the anode for LIBs, waste tire carbon shows a high specific capacity of 510.6 mAh·g^-1 at 100 mA·g^-1 with almost 97% capacity retention after 100 cycles. Even at a high rate of 1 A·g^-1, the carbon electrode presents an excellent cyclic capability of 255.1 mAh·g^-1 after 3000 cycles. This high-performance carbon material has many potential applications in LIBs and provide an alternative avenue for the recycling of waste tires.

Physicochemical properties and performance of graphene oxide/polyacrylonitrile composite fibers as supercapacitor electrode materials

Graphene oxide derived from palm kernel shells (rGOPKS) and polyacrylonitrile (PAN) were electrospun into composite fiber mats and evaluated as supercapacitor electrode materials. Their morphologies and crystalline properties were examined, and chemical interactions between rGOPKS and PAN were investigated. The diameters of individual fibers in the rGOPKS/PAN composite mats ranged from 1.351 to 1506 μm and increased with increasing rGOPKS content. A broad peak centered near 23° in the X-ray diffraction (XRD) pattern of rGOPKS corresponded to the (002) planes in graphitic carbon. Characteristic rGOPKS and PAN peaks were observed in the XRD patterns of all the composite fibers, and their Fourier-transform infrared (FTIR) spectra indicated hydrogen bond formation between rGOPKS and PAN. The composite fiber mats had smooth and homogeneous surfaces, and they exhibited excellent flexibility and durability. Their electrochemical performance as electrodes was assessed, and a maximum specific capacitance of 203 F g-1 was achieved. The cycling stability of this electrode was excellent, and it retained over 90% of its capacitance after 5000 cycles. The electrode had an energy density of 17 W h kg-1 at a power density of 3000 W kg-1. Dielectric results showed a nanofiber composite dielectric constant of 72.3 with minor leakage current (tan δ) i.e., 0.33 at 51 Hz. These results indicate that the rGOPKS/PAN composite fibers have great promise as supercapacitor electrode materials.

Disposable electrodes from waste materials and renewable sources for (bio)electroanalytical applications

The numerous advantages of disposable and screen-printed electrodes (SPEs) particularly in terms of portability, sensibility, sensitivity and low-cost led to the massive application of these electroanalytical devices. To limit the electronic waste and recover precious materials, new recycling processes were developed together with alternative SPEs fabrication procedures based on renewable, biocompatible sources or waste materials, such as paper, agricultural byproducts or spent batteries. The increased interest in the use of eco-friendly materials for electronics has given rise to a new generation of highly performing green modifiers. From paper based electrodes to disposable electrodes obtained from CD/DVD, in the last decades considerable efforts were devoted to reuse and recycle in the field of electrochemistry. Here an overview of recycled and recyclable disposable electrodes, sustainable electrode modifiers and alternative fabrication processes is proposed aiming to provide meaningful examples to redesign the world of disposable electrodes.

Universal Synthesis of Porous Inorganic Nanosheets via Graphene-Cellulose Templating Route

Two-dimensional (2D) inorganic nanomaterials have attracted enormous interest in diverse research areas because of their intriguing physicochemical properties. However, reliable method for the synthesis and composition manipulation of polycrystalline inorganic nanosheets (NSs) are still considered grand challenges. Here, we report a robust synthetic route for producing various kinds of inorganic porous NSs with desired multiple components and precise compositional stoichiometry by employing tunicin, i.e., cellulose extracted from earth-abundant marine invertebrate shell waste. Cellulose fibrils can be tightly immobilized on graphene oxide (GO) NSs to form stable tunicin-loaded GO NSs, which are used as a sacrificial template for homogeneous adsorption of diverse metal precursors. After a subsequent pyrolysis process, 2D metallic or metal oxide NSs are formed without any structural collapse. The rationally designed tunicin-loaded GO NS templating route paves a new path for the simple preparation of multicompositional inorganic NSs for broad applications, including chemical sensing and electrocatalysis.

Stacked-Cup Carbon Nanotube Flexible Paper Based on Soy Lecithin and Natural Rubber

Stacked-cup carbon nanotubes (SCCNTs) are generally referred to as carbon nanofibers (CNFs). SCCNTs are much less expensive to fabricate and are regarded as good polymer modifiers suitable for large-scale production. Flexible, SCCNT-based soy lecithin biocomposites were fabricated using liquid natural rubber latex as binder. Natural polymers and the SCCNTs were dispersed in a green solvent using a benchtop high-pressure homogenizer. The inks were simply brush-on painted onto cellulose fiber networks and compacted by a hydraulic press so as to transform into conductive paper-like form. The resulting flexible SCCNT papers demonstrated excellent resistance against severe folding and bending tests, with volume resistivity of about 85 Ω·cm at 20 wt % SCCNT loading. The solvent enabled formation of hydrogen bonding between natural rubber and soy lecithin. Thermomechanical measurements indicated that the biocomposites have good stability below and above glass transition points. Moreover, the SCCNT biocomposites had high through-plane thermal conductivity of 5 W/mK and 2000 kJ/m³K volumetric heat capacity, ideal for thermal interface heat transfer applications.

Conductive Polymer Composites from Renewable Resources: An Overview of Preparation, Properties, and Applications

This article reviews recent advances in conductive polymer composites from renewable resources, and introduces a number of potential applications for this material class. In order to overcome disadvantages such as poor mechanical properties of polymers from renewable resources, and give renewable polymer composites better electrical and thermal conductive properties, various filling contents and matrix polymers have been developed over the last decade. These natural or reusable filling contents, polymers, and their composites are expected to greatly reduce the tremendous pressure of industrial development on the natural environment while offering acceptable conductive properties. The unique characteristics, such as electrical/thermal conductivity, mechanical strength, biodegradability and recyclability of renewable conductive polymer composites has enabled them to be implemented in many novel and exciting applications including chemical sensors, light-emitting diode, batteries, fuel cells, heat exchangers, biosensors etc. In this article, the progress of conductive composites from natural or reusable filling contents and polymer matrices, including (1) natural polymers, such as starch and cellulose, (2) conductive filler, and (3) preparation approaches, are described, with an emphasis on potential applications of these bio-based conductive polymer composites. Moreover, several commonly-used and innovative methods for the preparation of conductive polymer composites are also introduced and compared systematically.

Cations mediating proton conductivity in an oxalate based microporous coordination polymer

Through cation substitution in a zirconium based coordination polymer, an isostructural framework 1@NH₄⁺ has been prepared without any apparent structural change. The proton conductivity of 1@NH₄⁺ is successfully improved. It exhibits high proton conductivity (1.39 × 10⁻² S cm⁻¹) at 98% relative humidity and 60 °C.

Recycled Carbon Fiber-Supported Polyaniline/Manganese Dioxide Prepared via One-Step Electrodeposition for Flexible Supercapacitor Integrated Electrodes

The exploration of multifunctional electrode materials has been a hotspot for the development of high-performance supercapacitors. We have used carbon fiber plates recovered from construction waste to prepare high-quality flexible carbon fiber materials by pyrolysis of epoxy resin. The as-prepared recycled carbon fiber has a diameter of 8 μm and is the perfect substrate material for flexible electrode materials. Furthermore, polyaniline and manganese dioxide are uniformly deposited on the recycled carbon fiber by one-step electrodeposition to form an active film. The recycled carbon fiber/polyaniline/MnO₂ composite shows an excellent specific capacitance of 475.1 F·g⁻¹ and capacitance retention of 86.1% after 5000 GCD cycles at 1 A·g⁻¹ in 1 M Na₂SO₄ electrolyte. The composites optimized for electrodeposition time have more electroactive sites, faster ions and electron transfer, structural stability and higher conductivity, endowing the composites promising application prospect.

Polyoxometalate-Based Metal-Organic Frameworks with Conductive Polypyrrole for Supercapacitors

Metal-organic frameworks (MOFs) with high porosity could act as an ideal substitute for supercapacitors, but their poor electrical conductivities limit their electrochemical performances. In order to overcome this problem, conductive polypyrrole (PPy) has been introduced and a novel nanocomposite resulting from polyoxometalate (POM)-based MOFs (NENU-5) and PPy has been reported. It comprises the merits of POMs, MOFs, and PPy. Finally, the highly conductive PPy covering the surfaces of NENU-5 nanocrystallines can effectively improve the electron/ion transfer among NENU-5 nanocrystallines. The optimized NENU-5/PPy nanocomposite (the volume of Py is 0.15 mL) exhibits high specific capacitance (5147 mF·cm^-2), larger than that of pristine NENU-5 (432 mF·cm^-2). Furthermore, a symmetric supercapacitor device based on a NENU-5/PPy-0.15 nanocomposite possesses an excellent areal capacitance of 1879 mF·cm^-2, which is far above other MOF-based supercapacitors.

Sustainable Waste Tire Derived Carbon Material as a Potential Anode for Lithium-Ion Batteries

The rapidly growing automobile industry increases the accumulation of end-of-life tires each year throughout the world. Waste tires lead to increased environmental issues and lasting resource problems. Recycling hazardous wastes to produce value-added products is becoming essential for the sustainable progress of society. A patented sulfonation process followed by pyrolysis at 1100 °C in a nitrogen atmosphere was used to produce carbon material from these tires and utilized as an anode in lithium-ion batteries. The combustion of the volatiles released in waste tire pyrolysis produces lower fossil CO2 emissions per unit of energy (136.51 gCO2/kW·h) compared to other conventional fossil fuels such as coal or fuel–oil, usually used in power generation. The strategy used in this research may be applied to other rechargeable batteries, supercapacitors, catalysts, and other electrochemical devices. The Raman vibrational spectra observed on these carbons show a graphitic carbon with significant disorder structure. Further, structural studies reveal a unique disordered carbon nanostructure with a higher interlayer distance of 4.5 Å compared to 3.43 Å in the commercial graphite. The carbon material derived from tires was used as an anode in lithium-ion batteries exhibited a reversible capacity of 360 mAh/g at C/3. However, the reversible capacity increased to 432 mAh/g at C/10 when this carbon particle was coated with a thin layer of carbon. A novel strategy of prelithiation applied for improving the first cycle efficiency to 94% is also presented.

Utilizing Waste Thermocol Sheets and Rusted Iron Wires to Fabricate Carbon-Fe3 O4 Nanocomposite-Based Supercapacitors: Turning Wastes into Value-Added Materials

The synthesis of porous activated carbon (specific surface area=1883 m²  g^-1 ), Fe₃ O₄ nanoparticles, and carbon-Fe₃ O₄ (C-Fe₃ O₄ ) nanocomposites from local waste thermocol sheets and rusted iron wires is demonstrated herein. The resulting carbon, Fe₃ O₄ nanoparticles, and C-Fe₃ O₄ composites are used as electrode materials for supercapacitor applications. In particular, C-Fe₃ O₄ composite electrodes exhibit a high specific capacitance of 1375 F g^-1 at 1 A g^-1 and longer cyclic stability with 98 % capacitance retention over 10 000 cycles. Subsequently, an asymmetric supercapacitor, namely, C-Fe₃ O₄ ∥Ni(OH)₂ /carbon nanotube device, exhibits a high energy density of 91.1 Wh kg^-1 and a remarkable cyclic stability, with 98 % capacitance retention over 10 000 cycles. Thus, this work has important implications not only for the fabrication of low-cost electrodes for high-performance supercapacitors, but also for the recycling of waste thermocol sheets and rusted iron wires for value-added reuse.

Neutron vibrational spectroscopic studies of novel tire-derived carbon materials

Sulfonated tire-derived carbons have been demonstrated to be high value-added carbon products of tire recycling in several energy storage system applications including lithium, sodium, potassium ion batteries and supercapacitors. In this communication, we compared different temperature pyrolyzed sulfonated tire-derived carbons with commercial graphite and unmodified/non-functionalized tire-derived carbon by studying the surface chemistry and properties, vibrational spectroscopy of the molecular structure, chemical bonding such as C-H bonding, and intermolecular interactions of the carbon materials. The nitrogen adsorption-desorption studies revealed the tailored micro and meso pore size distribution of the carbon during the sulfonation process. XPS and neutron vibrational spectra showed that the sulfonation of the initial raw tire powders could remove the aliphatic hydrogen containing groups ([double bond splayed left]CH₂ and -CH₃ groups) and reduce the number of heteroatoms that connect to carbon. The absence of these functional groups could effectively improve the first cycle efficiency of the material in rechargeable batteries. Meanwhile, the introduced -SO₃H functional group helped in producing terminal H at the edge of the sp² bonded graphite-like layers. This study reveals the influence of the sulfonation process on the recovered hard carbon from used tires and provides a pathway to develop and improve advanced energy storage materials.

FeOOH nanorod arrays aligned on eggplant derived super long carbon tube networks as negative electrodes for supercapacitors

A novel eggplant derived carbon tube network/FeOOH composite for supercapacitor applications was synthesized via freeze-drying, in situ carbonization and a hydrothermal method.

Eco-Friendly and High Performance Supercapacitors for Elevated Temperature Applications Using Recycled Tea Leaves

Used tea leaves are utilized for preparation of carbon with high surface area and electrochemical properties. Surface area and pore size of tea leaves derived carbon are controlled by varying the amount of KOH as activating agent. The maximum surface area of 2532 m2 g-1 is observed, which is much higher than unactivated tea leaves (3.6 m2 g-1). It is observed that the size of the electrolyte ions has a profound effect on the energy storage capacity. The maximum specific capacitance of 292 F g-1 is observed in 3 m KOH electrolyte with outstanding cyclic stability, while the lowest specific capacitance of 246 F g-1 is obtained in 3 m LiOH electrolyte at 2 mV s-1. The tea leaves derived electrode shows almost 100% capacitance retention up to 5000 cycles of study. The symmetrical supercapacitor device shows a maximum specific capacitance of 0.64 F cm-2 at 1 mA cm-2 and about 95% of specific capacitance is retained after increasing current density to 12 mA cm-2, confirming the high rate stability of the device. An improvement over 35% in the charge storage capacity is seen when increasing device temperature from 10 to 80 °C. The study suggests that used tea leaves can be used for the fabrication of environment friendly high performance supercapacitor devices at a low cost.

Materials Design and System Construction for Conventional and New-Concept Supercapacitors

With the development of renewable energy and electrified transportation, electrochemical energy storage will be more urgent in the future. Supercapacitors have received extensive attention due to their high power density, fast charge and discharge rates, and long-term cycling stability. During past five years, supercapacitors have been boomed benefited from the development of nanostructured materials synthesis and the promoted innovation of devices construction. In this review, we have summarized the current state-of-the-art development on the fabrication of high-performance supercapacitors. From the electrode material perspective, a variety of materials have been explored for advanced electrode materials with smart material-design strategies such as carbonaceous materials, metal compounds and conducting polymers. Proper nanostructures are engineered to provide sufficient electroactive sites and enhance the kinetics of ion and electron transport. Besides, new-concept supercapacitors have been developed for practical application. Microsupercapacitors and fiber supercapacitors have been explored for portable and compact electronic devices. Subsequently, we have introduced Li-/Na-ion supercapacitors composed of battery-type electrodes and capacitor-type electrode. Integrated energy devices are also explored by incorporating supercapacitors with energy conversion systems for sustainable energy storage. In brief, this review provides a comprehensive summary of recent progress on electrode materials design and burgeoning devices constructions for high-performance supercapacitors.

High-Performance Flexible Supercapacitors obtained via Recycled Jute: Bio-Waste to Energy Storage Approach

In search of affordable, flexible, lightweight, efficient and stable supercapacitors, metal oxides have been shown to provide high charge storage capacity but with poor cyclic stability due to structural damage occurring during the redox process. Here, we develop an efficient flexible supercapacitor obtained by carbonizing abundantly available and recyclable jute. The active material was synthesized from jute by a facile hydrothermal method and its electrochemical performance was further enhanced by chemical activation. Specific capacitance of 408 F/g at 1 mV/s using CV and 185 F/g at 500 mA/g using charge-discharge measurements with excellent flexibility (~100% retention in charge storage capacity on bending) were observed. The cyclic stability test confirmed no loss in the charge storage capacity of the electrode even after 5,000 charge-discharge measurements. In addition, a supercapacitor device fabricated using this carbonized jute showed promising specific capacitance of about 51 F/g, and improvement of over 60% in the charge storage capacity on increasing temperature from 5 to 75 °C. Based on these results, we propose that recycled jute should be considered for fabrication of high-performance flexible energy storage devices at extremely low cost.

Organic salt-derived nitrogen-rich, hierarchical porous carbon for ultrafast supercapacitors

Nitrogen-rich, high surface area, hierarchical porous carbons were simply prepared by the pyrolysis of a nitrogen-containing organic salt, and exhibit excellent rate capability in supercapacitors.

Superior Charge Storage and Power Density of a Conducting Polymer-Modified Covalent Organic Framework

The low conductivity of two-dimensional covalent organic frameworks (2D COFs), and most related coordination polymers, limits their applicability in optoelectronic and electrical energy storage (EES) devices. Although some networks exhibit promising conductivity, these examples generally lack structural versatility, one of the most attractive features of framework materials design. Here we enhance the electrical conductivity of a redox-active 2D COF film by electropolymerizing 3,4-ethylenedioxythiophene (EDOT) within its pores. The resulting poly(3,4-ethylenedioxythiophene) (PEDOT)-infiltrated COF films exhibit dramatically improved electrochemical responses, including quantitative access to their redox-active groups, even for 1 μm-thick COF films that otherwise provide poor electrochemical performance. PEDOT-modified COF films can accommodate high charging rates (10-1600 C) without compromising performance and exhibit both a 10-fold higher current response relative to unmodified films and stable capacitances for at least 10 000 cycles. This work represents the first time that electroactive COFs or crystalline framework materials have shown volumetric energy and power densities comparable with other porous carbon-based electrodes, thereby demonstrating the promise of redox-active COFs for EES devices.

Pseudocapacitive Electrodes Produced by Oxidant-Free Polymerization of Pyrrole between the Layers of 2D Titanium Carbide (MXene)

Heterocyclic pyrrole molecules are in situ aligned and polymerized in the -absence of an oxidant between layers of the 2D Ti3C2Tx (MXene), resulting in high volumetric and gravimetric capacitances with capacitance retention of 92% after 25,000 cycles at a 100 mV s(-1) scan rate.

Renewable pine cone biomass derived carbon materials for supercapacitor application

We report on the transformation of pine cone biomass into porous carbon via KOH activation and carbonization at 800 °C as electrode materials for supercapacitors.

Simultaneous reduction and covalent grafting of polythiophene on graphene oxide sheets for excellent capacitance retention

Herein, we report room temperature reduction and covalent grafting of GO sheets by thiophene derivatives to produce pseudocapacitive electrodes with high capacitance (230 F g⁻¹ at 1 mV s⁻¹) and most important, 100% cycling retention after 5000 cycles.