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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]