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The binder-free all-carbonaceous-component electrode was constructed by directly growing electroactive materials of nitrogen-doped carbon (NDC) on the substrate material of carbon paper (CP). The nitrogen-enriched polyaniline could be converted into NDC nanowires to cover on the surface of CP through electro-polymerization and carbonization processes. The polyaniline-derivated NDC electroactive material exhibits high capacity of 404.0 F g −1 at 1.0 A g −1 . The superior capacitance results from the good electron-donor properties of heterocyclic nitrogen distributed in the carbon skeleton and reversible redox reactivity of exocyclic nitrogen-containing functional groups at the edge of carbon skeleton. A low capacity decay of 22% indicates high rate capability when current density increases from 1.0 to 10 A g −1 . A high capacity retention ratio of 95.8% after 5000 cycles at 10.0 A g −1 presents good cycling stability. A symmetrical solid-state supercapacitor was constructed using NDC/CP electrode and polyvinyl alcohol-H 2 SO 4 gel electrolyte. The device delivers a specific capacitance of 187.1 F g −1 at 1.0 A g −1 , an energy density of 66.54 Wh kg −1 at the power density of 0.8 kW kg −1 , the capacity retention ratio of 94.1% after 5000 cycles at 5.0 A g −1 and an output voltage of 1.6 V, which is comparable to the reported state-of-the-art carbon-based supercapacitor. The all-carbonaceous-component electrode presents promising application in electrochemical energy storage devices. [ABSTRACT FROM AUTHOR]

Interfacial chemical bonding reinforced activated carbon fiber-m-aminobenzenesulfonic acid-polyaniline (ACF-mABSA-PANI) is designed as an electroactive supercapacitor electrode to achieve long cycle life and high capacitive performance. The ACF-mABSA-PANI molecular involves amide bond (–CO–NH–) between mABSA and ACF, as well as sulfonamide bond (–SO 2 –NH–) between mABSA and PANI. ACF-mABSA-PANI forms a π-π conjugated structure with enhanced electron delocalization and accelerated charge transfer, ultimately leading to reduced interfacial resistance, increased cycle life and superior capacitive performance. [Display omitted] • Bridge molecule-reinforced ACF-mABSA-PANI involves chemical bonding interaction. • ACF-mABSA-PANI shows higher cycle life and specific capacitance than ACF-PANI. • ACF-mABSA-PANI shows fast-Faradaic process dominated energy storage mechanism. • ACF-mABSA-PANI electrode is well used for braidable-supercapacitor application. The bridge molecule-reinforced activated carbon fiber-m-aminobenzenesulfonic acid-polyaniline (ACF-mABSA-PANI) is designed and fabricated as braidable-supercapacitor electrode to achieve long cycle life and high capacitive performance. The mABSA acts as bridge molecule to form amide bond between mABSA and ACF, as well as sulfonamide bond between mABSA and PANI, which is confirmed by infrared spectrometer and X-ray photoelectron spectroscopy. The interfacial interaction between ACF and PANI is enhanced by chemical bonding, thus alleviating the shedding of polyaniline and improving the cycle life of ACF-mABSA-PANI. The electrostatic potential and Mulliken charge analysis calculations indicate that ACF-mABSA-PANI has an extended delocalized π-π conjugation system. The bridge molecule of mABSA improves the free electron migration efficiency between PANI and ACF, leading to an increase in the specific capacitance of ACF-mABSA-PANI. As a result, ACF-mABSA-PANI presents much higher specific capacitance of 599.3F/g at 0.5 A/g and much higher capacitance retention ratio of 93.8 % after 2000 charge/discharge cycles at 2 A/g while ACF-PANI only keeps 335.0F/g and 54.4 %. Braidable-supercapacitor based on ACF-mABSA-PANI electrode provides an energy density of 39.83 Wh kg−1 at a power density of 900 W kg−1 and maintains a high capacitance retention of 78.1 % after 2000 charge/discharge cycles at 2 A/g. Well-designed ACF-mABSA-PANI presents the potential and promising application for wearable electrochemical energy storage devices. [ABSTRACT FROM AUTHOR]

The nickel (II) coordinated polyaniline (PANI-Ni) was designed as active electrode material to improve electrochemical cycling stability of conductive polymer-based supercapacitors. The conductive coordination polymer of PANI-Ni was formed to grow on the substrate of carbon paper through the hydrothermal coordination reaction between Ni(Ac) 2 and PANI. PANI-Ni with intrachain and interchain coordination structure could reinforce the polymer molecule chain strength to overcome volumetric swelling and shrinking during charge/discharge process. The specific capacitance was obviously improved from 234.5 F g −1 for bare PANI to 417 F g −1 for PANI-Ni in 1 M H 2 SO 4 electrolyte at a current density of 1 A g −1 and a potential window of 0.8 V. PANI-Ni electrode shows the cycling capacitance retention of 93% after 1000 cycles at 5 A g −1 . It also showed low capacitance loss of only 12% when the current density increased from 1 to 5 A g −1 , presenting high rate capability. The symmetric PANI-Ni supercapacitor was constructed using PANI-Ni electrode and H 2 SO 4 involved polyvinyl alcohol gel electrolyte. PANI-Ni supercapacitor showed the cycling capacitance retention of 83% after 1000 cycles at an output voltage of 1.7 V and a current density of 5 A g −1 . PANI-Ni conductive coordination polymer presents the promising application prospect of supercapacitor. [ABSTRACT FROM AUTHOR]

Carbon quantum dots-polyaniline (CQDs-PANI) hybrid was developed as supercapacitor electorde material by incorporating CQDs into PANI. PANI nanowires were grown vertically on carbon fiber substrate to form an interconnected network structure. Meanwhile, CQDs were uniformly distributed in the interior and on the surface of well-established net-like PANI nanowires. High specific capacitance of 738.3 F g −1 at 1.0 A g −1 was obtained for CQDs-PANI compared to that of 432.5 F g −1 for pure PANI. The capacitance retention after 1000 cycles of CQDs-PANI and PANI is 78.0% and 68.0% at 5.0 A g −1 , respectively. The high capacitance and reasonable cycle stability were ascribed to the incorporation of CQDs into PANI, which improved the conductivity and alleviated the volume change of the CQDs-PANI electrode during the charge/discharge process. In addition, a flexible solid-state CQDs-PANI supercapacitor was constructed using carbon paper as current collector and polyvinyl alcohol gel electrolyte, exhibiting the stable capacitive performance at planar and bending state. The specific capacitance, energy and power density were determined to be 169.2 mF cm −2 , 33.8 μWh cm −2 and 0.3 mW cm −2 at a potential window of 1.2 V and a current density of 1.0 mA cm −2 . CQDs-PANI presented the promising application in flexible energy-related device. [ABSTRACT FROM AUTHOR]

The flexible, freestanding polypyrrole/polyaniline (PPy/PANI) coaxial nanoarray was prepared by removing a titania (TiO2) sacrificial template from PPy/TiO2/PANI, which was initially formed by selectively coating PPy and PANI on the outer and inner surfaces of individual TiO2 nanotubes. PPy/PANI formed a hybrid coaxial structure of PANI nanorods encased in PPy nanopores. The PPy/PANI coaxial nanoarray exhibited a specific capacitance of 209.5 F g−1 at 0.5 A g−1, presenting higher performance than the PPy nanopore array (114.2 F g−1). Its capacitance decreased from 157.5 to 125.2 F g−1 after 500 cycles at 2.0 A g−1, presenting a reasonable capacitance retention of 79.5 %. The flexible supercapacitor based on the PPy/PANI coaxial nanoarray demonstrated a specific capacitance of 66 F g−1 at 0.5 A g−1. The PPy/PANI coaxial nanoarray exhibited high pseudocapacitance, moderate cyclibility, and good flexibility, suggesting its promising application in flexible energy storage devices. [ABSTRACT FROM AUTHOR]

The polypyrrole/titanium nitride/polyaniline (PPy/TiN/PANI) coaxial nanotube hybrid has been prepared as supercapacitor electrode material by stepwise loading of PPy and PANI into TiN nanotube array through normal pulse voltammetry and cyclic voltammetry electrodeposition process. P-type doping PPy and N-type doping PANI could be well incorporated into an integrated composite to act as an electroactive material. TiN nanotube array with highly ordered nanostructure and good electrical conductivity promoted the charge transfer capability of conducting polymers of PPy and PANI. PPy/TiN/PANI coaxial nanotube hybrid with P/N type doping properties exhibited high specific capacitance of 1471.9 F g −1 at a current density of 0.5 A g −1 and a potential window of 0.8 V in 1.0 M H 2 SO 4 solution. It could keep the capacitance of 1077.4 F g −1 at high current density of 10 A g −1 and capacitance retention of 78.0% after 200 cycles, presenting good rate capability and reasonable cycling stability. All-solid-state flexible supercapacitor was constructed using PPy/TiN/PANI electrode and H 2 SO 4 -included polyvinylalcohol gel electrolyte. It offered superior energy storage capacity with respect to specific capacitance of 288.4 F g −1 and energy density of 129.8 Wh kg −1 at high potential window of 1.8 V and current density of 1.0 A g −1 . PPy/TiN/PANI coaxial nanotube hybrid accordingly presented the promising application as supercapacitor electrode material for energy storage. [ABSTRACT FROM AUTHOR]

The ternary nanocomposite of polyaniline/carbon/titanium nitride (PANI/C/TiN) nanowire array (NWA) is fabricated as electroactive electrode material for flexible supercapacitor application. Firstly, TiN NWA is formed through ammonia nitridation treatment of TiO 2 NWA, which is synthesized via seed-assisted hydrothermal reaction. PANI/C/TiN NWA is then formed through sequentially coating carbon and PANI on the surface of TiN NWA. PANI/C/TiN NWA has unique shell/shell/core architecture, including a core layer of TiN NWA with a diameter of 40–160 nm and a length of 1.5 μm, a middle shell layer of carbon with a thickness of about 6.0 nm and an external surface layer of PANI with a thickness of 20–50 nm. PANI/C/TiN NWA provides ion diffusion channel at interspaces between the neighboring nanowires and electron transfer route along independent nanowires. The carbon shell layer is able to protect TiN NWA from electrochemical corrosion during charge/discharge process. PANI/C/TiN NWA displays high specific capacitance of 1093 F g −1 at 1.0 Ag −1 , and good cycling stability with a capacity retention of 98% after 2000 cycles, presenting better supercapacitive performance than other integrated nanocomposites of C/PANI/TiN, PANI/TiN and PANI/C/TiO 2 NWA. Such a ternary nanocomposite of PANI/C/TiN NWA can be used as an electrode material of flexible supercapacitors. [ABSTRACT FROM AUTHOR]

The polypyrrole/titania/polyaniline (PPy/TiO 2 /PANI) coaxial nanotube hybrid has been prepared through a stepwise electrodeposition process for an electrochemical energy storage. Independent TiO 2 nanotube array was used as the framework, which was formed by anodizing titanium foil at 30 V in fluoride-containing water and ethylene glycol mixture solution. The PPy was selectively coated on the outer surface of TiO 2 nanotube walls to form PPy/TiO 2 through a normal pulse voltammetry electrodeposition process. The PANI was then coated on the inner surface of TiO 2 nanotube walls to form PPy/TiO 2 /PANI coaxial nanotube hybrid through a photoassisted cyclic voltammetry electrodeposition process. The morphology and microstructure feature of PPy/TiO 2 /PANI were characterized by field-emission scanning electron microscopy and Raman spectrum. The capacitance performance was conducted by cyclic voltammetry and galvanostatic charge–discharge measurements. PPy/TiO 2 /PANI coaxial nanotube hybrid with P/N-type doping properties exhibited a high specific capacitance of 497 F g −1 at a current density of 0.5 A g −1 and a potential window of −0.2 to 0.8 V in 1.0 M H 2 SO 4 solution. The capacitance declined from 267.9 to 193.7 F g −1 after 500 cycles at a high current density of 2.0 A g −1 , showing 72.3% capacitance retention and a good cycle stability for the promising supercapacitor application. [ABSTRACT FROM AUTHOR]

Highlights: [•] PANI/TiN core–shell nanowire arrays were prepared for supercapacitor application. [•] TiN nanowire arrays contributed to high surface area and low resistance for PANI. [•] PANI/TiN core–shell nanowire arrays exhibited much higher capacitance than PANI/TiO2. [Copyright &y& Elsevier]

The polyaniline bonding with nitrogen doped MoS 2 (MoS x N y @PANI) was fabricated by hydrothermal vulcanization, nitrogen doping and electropolymerization process, which was designed as the stable structured supercapacitor electrode. The interface bonding interaction between conductive PANI and conductive MoS x N y is proposed to prove the feasibility of the coordination bond enforced hybrid electrode material by using experimental measurement and density functional theory simulation calculation. The MoS x N y involves an intermediate energy level to improve its electrical conductivity by lowering band gap from 1.45 to 0.65 eV. MoS x N y @PANI involves the interface Mo-N coordination bond between N atom of terminal amino group of PANI and the exposed Mo atom of MoS x N y. MoS x N y @PANI shows lower energy barrier (5.07 eV) and lower interface energy (1.41 eV) than MoS 2 @PANI (5.31 eV, 1.86 eV) due to interface Mo-N bonding, contributing to its highly improved structure stability. MoS x N y @PANI exhibits higher pseudocapacitive contribution (61.4%) than MoS x N y (47.4%) and MoS 2 (41.9%), indicating the Mo-N coordination-induced activation of PANI. MoS x N y @PANI electrode achieves high specific capacitance of 577 F g−1 and impressive capacitance retention of 85.3% after 3000 cycles even at high current density of 5 A g−1. Interface Mo-N coordination bonding MoS x N y @PANI with high electrochemical stability and capacitance performance exhibits the promising application as stable energy storage devices. [ABSTRACT FROM AUTHOR]

Bridge molecule thiourea (TU) enforced polyaniline (PANI) growing on activated carbon fiber (ACF) is applied to synthesize PANI-TU-ACF as flexible supercapacitor electrode material which involves an amide-bonding interface between ACF and TU, a hydrogen bonding interface between TU and PANI. [Display omitted] • Bridge molecular thiourea enforces interfacial interaction between ACF and PANI. • Amide bonding PANI and hydrogen bonding ACF improve cyclability of PANI-TU-ACF. • Bridging-structured PANI-TU-ACF is used for braidable-supercapacitor application. The bridge molecule thiourea (TU) enforced polyaniline (PANI) growing on activated carbon fiber (ACF) is applied to synthesize polyaniline-thiourea-activated carbon fiber (PANI-TU-ACF) through surface activation, hydrothermal treatment and electrochemical deposition processes for wearable braidable-supercapacitor. Experimental measurement and theoretical calculation demonstrate that PANI-TU-ACF involves amide bonding interface between ACF and TU and hydrogen bonding interface between TU and PANI, thus confirming the formation of bridging structure. The absorption spectrum red-shift of N–H vibration peak keeps in agreement with the declined bonding energy of N–H bond achieved by partial atom potential simulation calculation, which proves the formation of hydrogen bonding in PANI-TU-ACF. PANI-TU-ACF exhibits larger N(E) value and lower HOMO-LUMO energy gap than PANI-ACF, indicating its higher electrical conductivity. PANI-TU-PANI shows more lowered interface energy than PANI-ACF, suggesting its higher stability. PANI-TU-ACF electrode delivers excellent capacitance of 563.8F/g at 1 A/g and cycling stability of 89.1 % for 2000 cycles. Wearable braidable-supercapacitor based on PANI-TU-ACF electrode delivers energy density of 62.9 Wh kg−1 at power density of 800 W kg−1, maintains high capacitance retention of 90.13 % after 2000 charging/discharging cycles. The interfacial bonding strengthened PANI-TU-ACF with excellent performance displays potential in wearable supercapacitors. [ABSTRACT FROM AUTHOR]

• Hybrid membrane involves electroactive PANI layer and full crack-free carbon layer. • FC@NF shows superior electrochemical anti-corrosion performance in H 2 SO 4 electrolyte. • PANI@FC@NF achieves high capacitance and cycling stability in H 2 SO 4 electrolyte. Hybrid membrane of polyaniline layer/full carbon layer coating on nickel foam (PANI@FC@NF) is designed as supercapacitor electrode with superior anti-corrosion and capacitance performance in an acidic electrolyte. PANI@FC@NF is prepared by fully coating crack-free carbon layer on nickel foam (FC@NF) through hydrothermal and thermal carbonization of glucose, and then PANI layer is coated on FC@NF through the method of electrodeposition. FC@NF shows much lower corrosion current density (0.284 mA cm−2) and higher corrosion potential (-0.171 V) in 1.0 M H 2 SO 4 , compared with NF (7.208 mA cm−2 and -0.208 V). PANI@FC@NF electrode achieves specific capacitance of 610 mF cm−2 at 1.0 mA cm−2 and cycling capacitance retention of 77.63 % at 2.0 mA cm−2 after 1000 cycles in 0.5 M H 2 SO 4. All-solid-state symmetrical supercapacitor using PANI@FC@NF electrode and polyvinyl alcohol-H 2 SO 4 gel electrolyte achieves 41 μWh cm−2 at 0.9 mW cm−2 and an excellent cycling performance. [ABSTRACT FROM AUTHOR]