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Thiourea aldehyde resin-based heteroatom doping carbon and graphene composites (RHDC/GN) were prepared by an in situ polymerization and carbonization. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images showed that thiourea aldehyde resin deposited on lamellar GO flakes during the polymerization and RHDC/GN composites had a hierarchical structure. The specific capacitance of the RHDC/GN composites was high up to 355 F g, much higher than that of the pure thiourea aldehyde resin-based heteroatom doping carbon (RHDC) with specific capacitance of 135 F g at a current density of 1.0 A g in 6-M KOH electrolyte. And the hetroatoms in RHDC/GN composites increase the specific capacitance, and GN enhances the conductivity of the electrodes which is beneficial to improving electrochemical cycling stability of the electrode significantly. The specific capacitance retains 90.97% after 5000 charge-discharge processes at 10 A g, which provides potential as supercapacitors. [ABSTRACT FROM AUTHOR]

Nitrogen and sulfur porous co-doped carbonized materials were successfully prepared from polyurethane (PU) using KOH as an activating agent with promising electrochemical performances. Many micropores imbedded in the carbon materials are beneficial to electrolyte transport and the resulting specific surface area of the porous samples is up to 2216 m g measured by the N adsorption-desorption method. The electrochemical performances of the activated carbon samples were tested as supercapacitors in a three-electrode system and the Ragone plot was examined in a two-electrode cell with a 6 M KOH solution as electrolytes. The specific capacitance of porous carbon material PUC-2:1 (the mass ratio of KOH and PUC was 2:1 at an active temperature of 750 °C for 2 h) reaches 395 F g at the current density of 1 A g, and the capacitance retention is 95.3% after 4000 charge-discharge cycles at a large current density of 10 A g. The energy density of PUC-2:1 is 24.4 Wh kg at the power density of 1080 W kg and still retains 12.6 Wh kg with a high power density of 21.6 kW kg at a high current density of 10 A g. Such a high energy density at a large power density provides potential application in high performance of energy storage devices. [ABSTRACT FROM AUTHOR]

Well-dispersed resorcinol-formaldehyde-based carbon spheres (RFCs) have been prepared by the polycondensation of resorcinol and formaldehyde with ammonia as catalyst and subsequent carbonization of the obtained polymer. In situ polymerization of the aniline occurred in the suspension of the RFC, and RFC was surrounded by the polyaniline (PANI) wires. The PANI and RFC hybrid network (PRFC) formed gradually. In a three-electrode mode, the specific capacitance ( C ) of PRFC reaches 315 F g at a current density of 1 A g in 2 M HSO, much higher than that of pure PANI (225 F g) and RFC (121.7 F g). Furthermore, the C of PRFC retains 80.0 % after 1000 charge-discharge processes at a current density of 5 Ag. The enhanced electrochemical performance of the PRFC came from its homogeneous three-dimensional hierarchical network structure, good electric conductivity of the PANI around the RFC, and the synergistic effect between the RFC and PANI. [ABSTRACT FROM AUTHOR]

Using polypyrrole (PPy) nanotubes as the substrate, the layered molybdenum disulfide (MoS) nanosheets were wrapped on PPy nanotubes to form MoS/PPy nanocomposites by a hydrothermal reaction. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images showed that MoS nanosheets coated uniformly on the surface of PPy nanotubes owing to the electrostatic force. The specific capacitance of the MoS/PPy nanocomposites was high up to 307.5 F g, much higher than that of the pure PPy with specific capacitance of 106.3 F g and MoS with specific capacitance of 138.5 F g at a current density of 1.0 A g in 1 M KCl electrolyte. And the special structure of MoS/PPy nanocomposites electrode reduces the deformation during the charge-discharge process and thus improves the rate stability and electrochemical cycling stability of the electrode significantly. The specific capacitance retains 96.47 % after 1000 charge-discharge processes which provides potential as supercapacitors. [ABSTRACT FROM AUTHOR]