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Developing highly porous and conductive carbon electrodes are crucial for high-performance electrochemical double-layer capacitors. Herein, we provide a supercapacitor electrode material consisting of N-doped porous carbon tightly anchored on carbon nanotubes. This nanocomposite with high specific surface area of 659.5 m 2 g −1 is fabricated by pyrolyzing the ZIF-8/polypyrrole nanotubes. When the nanocompiste is used as supercapacitor electrodes, it deliveres high specific capacitance of 248 F g −1 and 97.3% of capacitance retention after 3000 cycles. The superior capacitive performance is attributed to the conductive network for electron transport constributed by CNTs and the abundant reservoir for the charge storage derived from ZIF-derived porous carbon. Benefiting from the unique structural features and high N doping, the PC-CNTs obtained by our route could be a promising candidate of electrode mateials for high-performance supercapacitors. [ABSTRACT FROM AUTHOR]

N-doped porous carbon nanosheets (N-CNS) were prepared from coal tar pitch with the addition of urea and KOH activation. In the synthesis route, urea plays an important role in constructing the 2D sheet-like structure, which serves as a nitrogen source, chemical blowing agent and the in-situ formation of g-C 3 N 4 self-degraded template. At a low activation temperature (600 °C), the as-prepared N-doped porous carbon nanosheets possess high nitrogen content (7.06 at. %) and high specific surface area (1181 m 2  g −1 ), which offers remarkable capacitive performances due to the unique architecture and pseudocapacitance contribution of the N doping. The N-CNS exhibits high capacitive performance (210 F g −1 at 0.1 A g −1 ), and an excellent cycling stability. Additionally, the assembled symmetric supercapacitor displays an energy density of 7.15 Wh kg −1 , and the capacitance retention remains 91.2% after 5000 cycles at 1 A g −1 . The facile and low-cost route to massively prepare N-doped porous carbon nanosheets from coal tar pitch would be favorable to the applications of carbon materials for high performance supercapacitors. [ABSTRACT FROM AUTHOR]

The porous carbon microtubes/flakes composites are prepared via a facile hydrothermal treatment with bamboo chopsticks as a carbon precursor and KOH as an activating agent. The as-prepared samples possess the large specific surface area up to 2337 m 2 g −1 . They exhibit the high specific capacitance of 212 F g −1 at a current density of 0.1 A g −1 , and the capacitance retention remains 96% after 1000 cycles in 6 M KOH. The results indicate that the natural resource of bamboo chopsticks could be an essential raw material for the energy storage devices. [ABSTRACT FROM AUTHOR]

In this paper, willow leaves were used to prepare activated carbons (ACs) by one-step pyrolysis with ZnCl 2 activation. The as-prepared AC-1-800 exhibits porous structure with high specific surface area of 1031 m 2 g −1 and a large pore volume of 0.66 cm 3 g −1 . As a supercapacitor electrode, it shows a good capacitive performance in 6 M of KOH aqueous electrolyte, such as the specific capacitance reaches 216 F g −1 at a current density of 0.1 A g −1 and the retention of specific capacitance is 97% after 1000 cycles at 2 A g −1 . [ABSTRACT FROM AUTHOR]