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N/P dual-doped three-dimensional porous carbon was synthesized via nano-CaCO 3 template-assistant carbonization of intumescent flame retardants (IFRs) precursor. [Display omitted] Heteroatom-doped three-dimensional (3D) porous carbons possess great potential as promising electrodes for high-performance supercapacitors. Inspired by the inherent features of intumescent flame retardants (IFRs) with universal availability, rich heteroatoms and easy thermal-carbonization to form porous carbons, herein we proposed a self-assembling and template self-activation strategy to produce N/P dual-doped 3D porous carbons by nano-CaCO 3 template-assistant carbonization of IFRs. The IFRs-derived carbon exhibited large specific surface area, well-balanced hierarchical porosity, high N/P contents and interconnected 3D skeleton. Benefitting from these predominant characteristics on structure and composition, the assembled supercapacitive electrodes exhibited outstanding electrochemical performances. In three-electrode 6 M KOH system, it delivered high specific capacitances of 407 F g−1 at 0.5 A g−1, and good rate capability of 61.2% capacitance retention at 20 A g−1. In two-electrode organic EMIMBF 4 /PC system, its displayed high energy density of 62.8 Wh kg−1 at a power density of 748.4 W kg−1, meanwhile it had excellent cycling stability with 84.7% capacitance retention after 10,000 cycles. To our best knowledge, it is the first example to synthesize porous carbon from IFRs precursor. Thus, the current work paved a novel and low-cost way for the production of high-valued carbon material, and expanded its application for high-performance energy storage devices. [ABSTRACT FROM AUTHOR]

Disposable aluminum cans and plastic bottles are common wastes found in modern societies. This article shows that they can be upcycled into functional materials, such as metal-organic frameworks and hierarchical porous carbon nanomaterials for high-value applications. Through a solvothermal method, used poly(ethylene terephthalate) bottles and aluminum cans are converted into MIL-53(Al). Subsequently, the as-prepared MIL-53(Al) can be further carbonized into a nitrogen-doped (4.52 at%) hierarchical porous carbon framework. With an optical amount of urea present during the carbonization process, the carbon nanomaterial of a high specific surface area of 1324 m2 g−1 with well-defined porosity can be achieved. These features allow the nitrogen-doped hierarchical porous carbon to perform impressively as the working electrode of supercapacitors, delivering a high specific capacitance of 355 F g−1 at 0.5 A g−1 in a three-electrode cell and exhibiting a high energy density of 20.1 Wh kg−1 at a power density of 225 W kg−1, while simultaneously maintaining 88.2% capacitance retention over 10,000 cycles in two-electrode system. This work demonstrates the possibility of upcycling wastes to obtain carbon-based high-performance supercapacitors. [Display omitted] • Upcycle used PET bottles and aluminum cans into the nitrogen-doped hierarchical porous carbons. • Prepared carbon as supercapacitor electrode delivers a high energy density of 20.1 Wh/kg. • Well-defined porous carbon framework is vital to the excellent supercapacitive performance. • This work paves an effective environmental-friendly way to prepare carbon-based supercapacitor. [ABSTRACT FROM AUTHOR]

The intrinsic properties and structural construction of active materials are crucial to improving the performance of electrodes. Herein, flexible and hydrophilic polyetherimide/polyaniline (PEI/PANI) conductive microfiber membranes with unique core-shell architecture were prepared via electrospinning followed by in-situ chemical oxidation polymerization of aniline doped with 2-acrylamido-2-methyl-1-propanesulfonic acid, and used to boost the properties through the combined action of the pseudocapacitive PANI and abundant porous PEI membranes. For achieving excellent PEI/PANI microfiber membranes as free-standing electrodes, the polymerization time was controlled to refrain from exceed PANI particles agglomeration and maintain the unique three-dimensional porous network structure. Optimized PEI/PANI microfiber membranes with the polymerization time of 7 h presented the best electrochemical properties with high specific capacitance of 249.5 F g−1 at 1 A g−1 and low charge-transfer resistance of 8.316 Ω. Ascribing to the combined effect between the unique pore structure of PEI microfiber membranes and pseudocapacitance of PANI, the flexible supercapacitor based on PEI/PANI-7 demonstrated exceptional capacitance (175.1 F g−1 at 1 A g−1), high energy density (43.4 Wh kg−1) and power density (34.0 kW kg−1), and outstanding flexibility while preserving the cyclic stability. Therefore, this free-standing PEI/PANI microfiber membranes could be deemed as a prospective electrode contender for flexible supercapacitor applications. [Display omitted] • Flexible PANI/PEI electrode was prepared by polymerization of aniline doped with AMPS. • Microstructure of PANI/PEI electrode could be tunable by polymerization time. • The combined action of PANI and PEI membranes boosted its electrochemical properties. • The highest specific capacitance of PANI/PEI observed 249.5 F g−1 at a 1 A g−1. • Supercapacitor based on PANI/PEI revealed excellent energy density and power density. [ABSTRACT FROM AUTHOR]

Designing porous and flexible electrodes with excellent electrochemical properties is crucial to fabricate high-performance flexible supercapacitors. Conductive polymer-based electrospun fibers are expected to be an ideal material for constructing flexible electrodes due to the enormous specific surface area, unique pore structure and inherent flexibility. However, the exploration of such electrospun fibers with facile preparation methods and high areal capacitance remains challenging. Herein, a novel polyetherimide@polyaniline core-shell fibrous membranes (PEI@PANI CFMs) is fabricated via simply coaxial electrospinning and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) secondary doping. With the aid of polyetherimide, highly concentrated emeraldine base polyaniline (EB-PANI) can be perfectly wrapped on the surface of fibers without any spinning assistants, ensuring the well-developed pore structures, superior hydrophilicity, good electrical conductivity and outstanding mechanical flexibility. Benefiting from the synergistic effect of structure and constituents, such flexible PEI@PANI CFMs as electrode materials can provide more accessible electrochemical active sites and decrease the ion diffusion resistance. Therefore, the PEI@PANI CFMs present outstanding areal capacitance of 1159.9 mF cm−2 and remarkable energy density of 46.91 μW h cm−2 in the electrodes and symmetric supercapacitors, demonstrating great potential for applications in flexible energy storage field. This fabrication strategy provides a simple and practicable way to manufacture polyaniline-based fibrous membranes for high-performance flexible electrode materials. [Display omitted] • PEI@PANI CFMs were firstly developed by coaxial electrospinning with high density PANI solution. • Continuous PANI shell without spinning assistants enabled high redox activity after AMPS doping. • PEI@PANI CFMs showed unique 3D network pore structure, superior hydrophilicity and flexibility. • PEI@PANI CFMs as electrode exhibited 1159.9 mF cm−2 area specific capacitance at 1 mA cm−2. • The symmetric device delivered remarkable energy density of 46.91 μW h cm−2 at 0.23 mW cm−2 [ABSTRACT FROM AUTHOR]